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Guidelines Part 5

Guidelines Part 5 Contents

DEFINITIONS

  G5.1.1 Biological agents new

WORKPLACE HAZARDOUS MATERIALS INFORMATION SYSTEM (WHMIS)

  G5.3-1 WHMIS Application
  G5.3-2 Fire extinguishers
  G5.3-3 Cylinders of breathing air
  G5.3-4 Exemptions
  G5.3-5 Leaded glaze materials
  G5.3-6 "For industrial use only" labels
  G5.3-7 Warehousing of Controlled Products
  G5.3-8 Application of WHMIS in agriculture
  G5.5 WHMIS program
  G5.6 Worker education
  G5.8-1 Supplier label
  G5.8-2 Labelling on leased or rented chemical application units
  G5.8-3 Multi-container shipments of laboratory samples
  G5.14-1 Supplier material safety data sheet (MSDS)
  G5.14-2 Fees
  G5.15 Laboratory MSDS

CONTAINERS AND STORAGE

  G5.22 Covers
  G5.25 Storage practices

FLAMMABLE AND COMBUSTIBLE SUBSTANCES

  G5.30 Dispensing

SUBSTANCES UNDER PRESSURE

  G5.38 Handling and securing cylinders

CONTROLLING EXPOSURE

Table of Exposure Limits for Chemical and Biological Substances
  G5.48-1 Exposure limits - Tables
  G5.48-2 Annual revisions to exposure limits
  G5.48-3 Normal 8-hour work period
  G5.48-4 Conversions for ppm and mg/m3
  G5.48-5 Welding fume
  G5.48-6 Allergenic species of wood dust
  G5.48-7 Nuisance dusts
  G5.48-8 Simple asphyxiants - Inert gases or vapours
  G5.48-9 Measuring compliance with the exposure limits
  G5.48-10 Use of indicator tubes to measure compliance
  G5.49 Application of excursion limits
  G5.50 Extended work periods
  G5.51 Additive effects
  G5.52 Skin notation
  G5.53-1 Workplace monitoring
  G5.53-2 Assessing compliance -- the walk-through survey
  G5.53-3 Monitoring worker exposure
  G5.53-4 Occupational hygiene methods acceptable to the Board
  G5.54-1 Exposure control plan
  G5.54-2 Elements of an exposure control plan
  G5.54-3 Risk identification, assessment and control
  G5.54-4 Hygiene facilities and decontamination procedures
  G5.54-5 Health monitoring
  G5.54-6 Documentation
  G5.54-7 Drywall sanding requirements
  G5.55 Type of controls
  G5.56 Oxygen deficiency
  G5.57 Designated substances
  G5.58 Protective policy
  G5.59 Investigating symptoms


VENTILATION

  G5.62 Submitting plans
  G5.63 Building modification
  G5.70 Discharged air

INTERNAL COMBUSTION ENGINES

  G5.73 Engine servicing and work area assessment for mobile equipment operated indoors
  G5.75 Mobile equipment emission controls

HAZARDOUS WASTES AND EMISSIONS

  G5.80 Hazardous wastes and emissions - Sharp-edged waste

PERSONAL HYGIENE

  G5.82 Employer's responsibility
  G5.83 Worker's responsibility

EMERGENCY WASHING FACILITIES

  G5.85 Where required
  G5.86 Water supply
  G5.88 Risk assessment
  G5.89 Table 5-3: Provision and location of emergency washing equipment
  G5.90 Mobile shower units
  G5.91 Remote worksites
  G5.93 Testing and maintenance
  G5.94 Training
  G5.95 Protection from freezing

EMERGENCY PROCEDURES

  G5.97 Emergency plan
  G5.99 Risk assessment
  G5.101 Procedures for spill cleanup and re-entry

Guidelines Part 5 - Definitions

G5.1.1 Biological Agents  new

Issued February 1, 2008

Regulatory excerpt
Section 5.1.1 of the OHS Regulation ("Regulation") states:

For the purposes of section 5.2 and sections 6.33 to 6.40, the following biological agents are designated as hazardous substances:
    (a) a liquid or solid material that is contaminated with a prion, virus, bacterium, fungus or other biological agent that has a classification given by the World Health Organization or Health Canada, as amended from time to time, as a Risk Group 2, 3 or 4 human pathogen that causes an adverse health effect;
    (b) a biological toxin that causes an adverse health effect.

Purpose of guideline
This guideline provides information on Risk Groups 2, 3 and 4 human pathogens that cause adverse health effects.

Risk Groups
Risk Groups 2, 3, and 4 are a component of a universally agreed to classification system as adopted by the World Health Organization (WHO) and Health Canada, among other jurisdictions. This system is based on the biosafety containment classification system developed by the WHO, and the Public Health Agency of Canada (PHAC).

The following provides an overview of each Risk Group.

Risk Group 2: A pathogen that can cause human or animal disease but under normal circumstances is unlikely to be a serious hazard to healthy laboratory workers, the community, livestock, or the environment. Laboratory exposures rarely cause infection leading to serious disease; effective treatment and preventive measures are available and the risk of spread is limited. They are considered to represent a moderate risk to individuals and a limited risk to the community. Examples of Risk Group 2 pathogens include the Hepatitis B and Hepatitis C viruses, salmonella, and E. coli bacteria.

Risk Group 3: A pathogen that usually causes serious human or animal disease, or which can result in serious economic consequences but does not ordinarily spread by casual contact from one individual to another, or that can be treated by antimicrobial or antiparasitic agents. They are considered to represent a high risk to individuals but a low risk to the community. Examples of Risk Group 3 pathogens include the human immunodeficiency virus (HIV), the virus causing Creutzfeldt-Jacob disease, hantavirus, and tuberculosis.

Risk Group 4: A pathogen that usually produces very serious human or animal disease, often untreatable, and may be readily transmitted from one individual to another, or from animal to human or vice-versa directly or indirectly, or by casual contact. They are considered to represent a high risk to both the individual and the community. Examples of Risk Group 4 pathogens are the hemorrhagic fever viruses such as Ebola, Marlburg, and Lassa.

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Guidelines Part 5 - Workplace Hazardous Materials Information System (WHMIS)

G5.3-1 WHMIS Application

Effective August 1, 1999; Editorial Revision January 2005

(1) Sections 5.3 to 5.19 (the WHMIS Requirements) apply to employers and workers with respect to controlled products used, stored or handled at a workplace, except as provided in subsections (2) to (4).

(2) The provisions concerning a supplier label and MSDS do not apply if the controlled product is

(a) an explosive within the meaning of the Explosives Act (Canada),

(b) a cosmetic, device, drug or food within the meaning of the Food and Drugs Act (Canada),

(c) a control product within the meaning of the Pest Control Products Act (Canada),

(d) a prescribed substance within the meaning of the Atomic Energy Control Act (Canada) or any successor legislation, or

(e) a product, material or substance packaged as a consumer product and in quantities normally used by the consuming public.

(3) The provisions do not apply if the controlled product is

(a) wood or a product made of wood,

(b) tobacco or a product made of tobacco,

(c) a manufactured article, or

(d) being transported or handled pursuant to the requirements of the Transportation of Dangerous Goods Act, 1992 (Canada) or the Transport of Dangerous Goods Act.

(4) The provisions do not apply to a hazardous waste, except that the employer must ensure the safe storage and handling of a hazardous waste generated at the workplace through the combination of worker education and the information required by this Regulation.

Note: For products partially or completely exempted from WHMIS by subsections (2) to (4), the general information requirements of section 5.2 must be met. Also, information requirements are specified elsewhere for particular groups of substances, for example, hazardous wastes in sections 5.76 to 5.81; pesticides in Part 6 (Substance Specific Requirements), and explosives in Part 21 (Blasting Operations).

"Controlled product" is defined in section 2 of the federal Hazardous Products Act as "any product, material or substance specified by the regulations...to be included in any of the classes listed in Schedule II." Schedule II sets out the following classes:

    Class A - Compressed Gas

    Class B - Flammable and Combustible Material

    Class C - Oxidizing Material

    Class D - Poisonous and Infectious Material

    Class E - Corrosive Material

    Class F - Dangerously Reactive Material

The contents of these classes are set out in the Controlled Products Regulations made under the Hazardous Products Act.

G5.3-2 Fire extinguishers (adopted from WHMIS Bulletin #4)

Effective August 1, 1999

Any extinguisher pressurized to more than 2.71 atmospheres (40 psi) at 21.1°C (70°F) meets the criterion for inclusion in WHMIS Class A, Compressed Gases. Some retardants (or performance additives to prevent effects such as freezing or corrosion) may meet criteria for inclusion in WHMIS Class D, Poisonous and Infectious Materials. (In addition, older soda-acid extinguishers will fall into WHMIS Class E.) Refer to sections 34 and 43 of the Controlled Products Regulations.

Fire extinguishers do not qualify for exemption from WHMIS as manufactured articles, as per section 12(1) of the Hazardous Products Act, because under normal conditions of use they will expose workers to a compressed gas or other controlled products.

The following stipulations apply (except in the case described in the *NOTE below) to fire extinguishers intended for use in the workplace and that meet criteria for inclusion in WHMIS because of a compressed gas, toxic effect or other criteria.

  • Suppliers who sell extinguishers for use in the workplace must apply WHMIS supplier labels to the extinguishers and provide an MSDS (see definition for supplier label in section 5.1 of the OHS Regulation as well as section 5.8).
  • A firm which recharges a fire extinguisher for an employer must apply a WHMIS supplier label to the extinguisher and provide an MSDS, if these are not already applied and provided. (Note: where an employer recharges extinguishers "in house" a workplace label will suffice if a supplier label is not already on the extinguisher.)
  • A detachable pressurized cartridge used to pressurize a dry chemical extinguisher must be provided with a WHMIS label (in addition to the label on the extinguisher) unless the cartridge is immediately installed on the extinguisher after the cartridge is pressurized. Suppliers who pressurize such cartridges must provide a supplier label; employers who pressurize their own cartridges must provide, at minimum, a workplace label. Labels must be applied to individual cartridges unless an alternative acceptable arrangement is used. (An example of an acceptable alternative is to provide a WHMIS label on the container of individual cartridges as long as cartridges are immediately installed on the extinguisher after being removed from the container. Where a supplier and employer wish to adopt this alternative or any arrangement in which the employer undertakes to apply supplier labels to cartridges contained in an outer container, the employer must establish the arrangement in writing.)

A generic MSDS covering both the cartridge and the extinguisher will be considered acceptable for the purposes of providing an MSDS on the cartridge.

*NOTE:
Extinguishers which contain aliphatic halogenated hydrocarbons and are packaged in a size of container which is sold on a retail basis to the public may, in lieu of a WHMIS label and MSDS, bear a consumer label consistent with consumer labelling and packaging requirements under the Hazardous Products Act.

G5.3-3 Cylinders of breathing air (adopted from WHMIS Bulletin #5)

Effective August 1, 1999

What are the requirements to provide labels, MSDS and worker education and training on compressed gas cylinders of breathing air?

Compressed air cylinders used in self-contained breathing apparatus fall into WHMIS Class A, Compressed Gases.

Provincial requirements (for cylinders filled in-house)

  • Material Safety Data Sheets: MSDS's must be provided for synthetic mixtures of breathing gases. For cylinders of compressed respirable atmospheric air, an MSDS will not be required, as this air must meet the air quality required by the OHS Regulation.
  • Labels: Workplace labels specifying the product identity and reference to the MSDS are required on synthetic mixtures of breathing gases. Safe handling instructions must be provided through the worker education and training program. For cylinders of respirable atmospheric air which are identifiable to workers by size and shape, for which an MSDS is not required, and where worker instruction in the safe use of the SCBA is in place as required by part 8 of the OHS Regulation, further labelling or means of identification is not necessary.

Federal requirements (for pressurized cylinders sold or imported, or filled on contract)

  • Suppliers who provide cylinders with compressed synthetic mixtures for breathing purposes for use in a workplace must apply supplier labels and provide MSDS's.
  • Suppliers who provide cylinders with compressed atmospheric air for breathing purposes for use in the workplace will not be required to provide an MSDS and a reference to the MSDS on the supplier label on condition that the supplier label:
  • includes all other six elements (the product and supplier identifiers, Class A hazard symbol, specific risk phrases and precautionary statements, and first aid measures where appropriate),
  • is surrounded by the WHMIS border, and
  • includes a precautionary statement to the effect "Ensure cylinder is filled with air meeting the quality standards of the local regulatory agency".

NOTE:
If an outside contractor (who is not the original supplier of the cylinder) refills cylinders with atmospheric air, the contractor would be required only to provide his/her supplier identifier if the original supplier label was illegible. Otherwise, the contractor would be required to provide a supplier label as per the second bullet above.

G5.3-4 Exemptions (adopted from WHMIS Bulletin #9)

Effective August 1, 1999

Partially exempted products

Section 5.3(2) of the OHS Regulation exempts controlled products covered under subsections (a) to (e) only from the requirements for a supplier label and a material safety data sheet. All other aspects of the WHMIS program apply, including sections 5.6 and 5.7. In order that the employer can meet obligations for education and training of staff, he/she must search for hazard information and will normally approach the supplier first. While an MSDS is the obvious solution, the supplier may provide information in any format. If an MSDS is provided, it need not meet all the requirements that govern a WHMIS MSDS, but should contain sufficient information to allow safe use, handling and storage of the controlled product. Suppliers are encouraged to provide an MSDS meeting WHMIS standards.

Completely exempted products

Controlled products falling into the categories in section 5.3(3) of the OHS Regulation are exempt from all aspects of the federal and provincial WHMIS regulations. The requirement for information on these materials falls within the scope of section 5.2 of the OHS Regulation. Provision of MSDS by suppliers will assist employers in meeting their obligations under these sections.

Hazardous wastes

Under section 5.3(4) of the OHS Regulation an employer is responsible for providing sufficient information for safe handling and storage of a hazardous waste generated at that place of employment. Since the employer has first hand knowledge about the process generating the hazardous waste, it falls to the employer to identify the material and educate the employees. Information from MSDSs for waste components or precursors combined with the process knowledge will be the source of the information given to employees.

NOTE:

  • The information required for partially and completely exempted products and wastes will cover items such as hazards (toxicity, fire and explosion, reactivity), storage information, safe work procedures, protective equipment, spill, leakage and fire-fighting information, and first aid measures. No matter whether the controlled product is included fully in the WHMIS program or is partially or completely exempted, employees must know the hazard(s), how to protect themselves in normal work and in emergency situations, and where to find more information when it is needed.
  • For consumer products which are partially exempt from federal WHMIS requirements, WHMIS Core Material (1989) states "In such cases, the supplier is encouraged to make an MSDS available on request" (p. 2-59).
  • For pesticides, which are partially exempt, Agriculture Canada has stated in the Memorandum to Registrants #R-1-235 "It is possible that MSDS's may become mandatory for pesticides. Registrants are encouraged to supply, on a voluntary basis, MSDS's on their actives/products in a WHMIS format."
G5.3-5 Leaded glaze materials (adopted from WHMIS Bulletin #11)

Effective August 1, 1999

Section 5.3(2)(e) of the OHS Regulation partially exempts "a product, material or substance packaged as a consumer product and in quantities normally used by the consuming public". This is based on section 12(f) of the Hazardous Products Act, which excludes from the provisions governing "controlled products" a "product, material or substance included in Part II of Schedule I and packaged as a consumer product". Item 31 in Part II of Schedule 1 refers to paints, enamels and other liquid coatings for use on the interior or exterior surfaces of buildings, furniture or household products that contain more than 0.5% by weight of lead.

How does the "consumer products exemption" apply to glaze materials sold or imported to the workplace?

  • Powdered glaze materials, which meet criteria as controlled products are covered by WHMIS.

  • Liquid glaze materials, which meet criteria as controlled products do not qualify for the consumer (restricted) products exemption as "liquid coatings" irrespective of lead content and are always subject to WHMIS information requirements when sold or imported to the workplace.

NOTE:
Suppliers are advised that the Liquid Coatings Materials Regulations administered by Health Canada prohibit the advertising, sale or importation to consumers of liquid coatings (such as paints) with more than 0.5% by weight of lead unless the product has required consumer product labelling and is for use on the exterior surfaces of buildings, or on the interior surfaces of (or furniture in) industrial or commercial premises or any other premises not likely to be used or frequented by children.

G5.3-6 "For industrial use only" labels (adopted from WHMIS Bulletin #10)

Effective August 1, 1999

Do phrases such as "For Industrial Use Only" and "For Professional Use Only" where they appear on labels of containers of controlled products legally imply that the product is "intended for use in the workplace" and that the product is subject to WHMIS information requirements?

  • The phrases "For Industrial Use Only" and "For Professional Use Only" imply intent for product use in the workplace. Where the product is a controlled product WHMIS requirements apply.
  • The supplier has the alternative of removing such phrases from the label in order to qualify for any exemption permitted (for example as a consumer product).
G5.3-7 Warehousing of Controlled Products

Issued February 27, 2001

This guideline clarifies the application of the Occupational Health & Safety Regulation relative to federal requirements when a controlled product is "handled" in a warehouse. Section 5.3(3)(d) of the Occupational Health & Safety Regulation states, in part, that the provisions of the WHMIS requirements "do not apply if the controlled product is being transported or handled pursuant to the requirements of the Transportation of the Dangerous Goods Act, 1992 (Canada) or the Transport of Dangerous Goods Act."

The Transportation of Dangerous Goods Act defines handling as "loading, unloading, packing or unpacking dangerous goods in a means of containment or transport for the purpose of, in the course of, or following transportation and includes storing them in the course of transportation." Handling in this context does not include actual use of a controlled product. TDG requirements deal primarily with acute exposures and the use of symbol alerts and placards. Transportation workers are not expected to be exposed to hazards associated with the controlled product unless there is an emergency, short-term circumstance such as a transport vehicle accident and spill. Conversely, worker exposure to controlled products in a workplace can occur in a wider variety of circumstances and over a longer period of time. Hence, WHMIS requirements are more extensive than TDG and include the use of explicit labels and material safety data sheets.

Application of WHMIS or TDG depends on the flow of goods through commerce as outlined in the following flow chart (adapted from the WHMIS Core Material Manual). WHMIS requirements are meant to apply at points of sale or use rather than during shipment. Transportation generally means to and from workplaces.

Figure 5.3 Flow of goods through commerce - where WHMIS and TDG requirements apply

Figure 5.3 Flow of goods through commerce - where WHMIS and TDG requirements apply

WHMIS, both federal (labels and MSDSs) and provincial (education and training, workplace labels), applies where controlled products are used, processed or repackaged in a warehouse. When warehoused, controlled products can be:

  • In "trans-shipment" (held in temporary storage between points of shipment)

  • Repackaged (assembled, packaged, labelled or relabelled)

  • Used

OHS Regulation sections 5.2(c) and 5.2(d) are non-WHMIS "general information requirements" that apply to a transshipment warehouse where in the case of an emergency or spill of a controlled product, an emergency response system must be established. This requires written emergency and spill cleanup procedures, and effective supervisor and worker training in these procedures.

A controlled product that is repackaged or used is subject to the WHMIS section of the OHS Regulation since workers may be exposed to the hazards of the controlled product.

The following table sets out the legislation and resources that apply to controlled products in a warehouse:

  Federal Provincial -- Occupational Health and Safety Regulation Other
Transshipment TDG Non-WHMIS sections
[5.2(c) & 5.2(d)]
CANUTEC*
Repackaging HPA/CPR** WHMIS sections
(5.3 -- 5.19)
 
Used HPA/CPR WHMIS sections
(5.3 -- 5.19)
 

Notes to table:
* CANUTEC (Canadian Transport Emergency Centre), part of the TDG Directorate, Transport Canada, provides hazard information in case of transport-related emergencies situations. Phone: (613) 996-6666.
** HPA/CPR (Hazardous Products Act/Controlled Products Regulations)

G5.3-8 The application of WHMIS in agriculture

Issued January 1, 2005

This guideline provides information to farmers, ranchers and agriculture workers on the general framework of the Workplace Hazardous Materials Information System (WHMIS), the application of regulatory requirements to partially and completely exempted products, and the means of forwarding concerns to the WCB about products for which suppliers are not providing information meeting WHMIS requirements.

The Workplace Hazardous Materials Information System (WHMIS) was developed in 1988 as a major step in helping to ensure that employers and workers would be provided with information on the hazards and control measures for hazardous materials (termed "controlled products") in the workplace. The requirements were made applicable to agriculture in 1993.

Application to suppliers and workplaces

Broadly speaking, WHMIS applies on two levels.

  • Suppliers: The suppliers of controlled products are required, under federal legislation, to provide information to employers for controlled products used in the workplace. Typically, the information must be provided in two ways: container labels, and material safety data sheets (MSDS).
  • Workplace: Employers are required, under provincial legislation, to ensure controlled products received in the workplace have the necessary labels and MSDS, and to ensure that workers are educated and trained in the safe use of the products. Other obligations apply, for example, if a controlled product is transferred from the supplier container to another container in the workplace it is necessary to label or identify the workplace container. Sections 5.3 to 5.19 of the OHS Regulation cover the provincial WHMIS requirements.

Partially and completely exempt products

As shown in section 5.3 of the OHS Regulation, there are different degrees to which controlled products are covered by WHMIS.

Many industrial products are fully covered by WHMIS, meaning the supplier requirements for labels and MSDS apply, and the employer must ensure that workplace obligations under WHMIS are also met. Examples of such products in agriculture include compressed gas cylinders used in welding operations, fuel products on site, and some acids and caustics.

Some products are partially exempt. Examples include pesticides and drugs (including some sterilants and disinfectants). In these cases there isn't a federal requirement for WHMIS labels and MSDS, but typically the products must meet other federal labeling and information requirements specific to them. In the case of pesticides and some other partially exempt products, suppliers will often provide MSDS, and the buyer should obtain an MSDS wherever available. The employer must meet provincial WHMIS requirements for information, education and training of workers and other matters such as workplace labels, as covered in sections 5.3-5.19 of the OHS Regulation. See OHS Guideline 5.3-4 for more information on partially exempt products.

Also, note that section 6.75 of the OHS Regulation requires that employers make readily available to workers an MSDS or its written equivalent for pesticides used at the workplace. Obtaining an MSDS from the pesticide supplier will help ensure that the requirement is met. An MSDS compliant with WHMIS will include information on nine categories of:

  • Product information
  • Hazardous ingredients
  • Physical data
  • Fire and explosion hazard
  • Reactivity data
  • Toxicological properties
  • Preventive measures
  • First aid measures
  • Preparation information

If the MSDS does not fully meet WHMIS standards, but has sufficient information to ensure the health and safety of workers using, transporting or storing the product, the MSDS may be considered acceptable. See OHS Guideline 6.75 for a list of the information that would be considered equivalent.

Some products such as welding rods, which are manufactured articles, are completely exempt from both the federal and provincial WHMIS requirements. In such cases, where the article contains a hazardous material the employer is encouraged to obtain an MSDS if available. Section 5.2 of the OHS Regulation addresses general information requirements for any chemical or biological substance that could cause an adverse health effect, and would apply in this case. Section 5.2 covers general responsibilities to identify the hazards of the substance, educate the worker, and implement and follow safe work procedures. See OHS Guideline 5.3-4 for more information on completely exempt products.

What if a supplier is not providing adequate labels or MSDS where required by WHMIS?

The question has arisen of what can be done to ensure up-to-date MSDS and labels are received from suppliers where federal WHMIS requirements apply to controlled products sold to farmers and ranchers. A nationwide WHMIS administrative system involving all Canadian OHS jurisdictions is in place to help deal with this issue.

Where an agricultural workplace is unable to get the proper WHMIS information for a controlled product from the supplier or distributor, the farmer or rancher is encouraged to contact the WCB at the WorkSafe Call Centre (604) 276-3100 (long distance toll free at 1-888-621-7233), or the WCB Regional Office nearest you. Many of the WCB occupational hygiene officers are designated to enforce federal WHMIS requirements on suppliers and distributors in this province. Where a distributor is providing product from elsewhere in Canada, the WCB will forward the concern to the responsible jurisdiction for their follow-up with the supplier.

For more information on the application of WHMIS, see the WCB publication, WHMIS at Work, which is available on the WCB web site at www.WorkSafebc.com

G5.5 WHMIS program (adopted from WHMIS Bulletin #1)

Effective August 1, 1999

Section 5.5 of the OHS Regulation states "If controlled products are used in the workplace the employer, in consultation with the occupational health and safety committee, if any, or health and safety representative, if any, must establish and maintain an effective WHMIS program, as part of the overall workplace health and safety program, which

(a) addresses applicable WHMIS Requirements including education and training, and

(b) is reviewed at least annually, or more frequently if required by a change in work conditions or available hazard information."

What is the interpretation of the phrase, "in consultation with the joint occupational health and safety committee" where it applies to the development and implementation of the program of WHMIS instruction?

Consultation means meeting for the purpose of seeking information or advice. An employer has consulted with the joint occupational health and safety committee regarding the program of WHMIS instruction if two conditions are met:

  • Prior to the finalization of the program of instruction the Committee has the opportunity to review and provide information or advice on the entire program including its content, structure and means of implementation. Content means education in "how WHMIS works", education in the hazards of controlled products and training in work procedures as itemized in section 5(7)(a) to (d). Means of implementation include choice of instructors and the use of any in-course evaluation.
  • On completion of the implementation of the program of instruction, the employer asks for information and advice from the Committee on the effectiveness of the program.

Where a number of committees has been established in a large workplace, an acceptable arrangement is for the lead (master/central) committee to review the employer's general plan for WHMIS instruction covering the entire workplace, and for satellite (local) committees to review the program of instruction in the areas of their respective responsibilities.

G5.6 Worker education (adopted from WHMIS Bulletin #8)

Effective August 1, 1999

Section 5.6 of the OHS Regulation provides for worker education concerning the WHMIS system. Section 5.7 requires the employer to instruct the worker in the work procedures for implementing WHMIS.

Following are four questions to ask workers to check for adequacy of education and training on controlled products to which workers may be exposed.

What are the hazards of the controlled product?

The answer must reflect the possible adverse effects of the products in question. This demonstrates an understanding of generic hazard information (education).

How are you protected from those hazards?

The answer must demonstrate a worker understanding of proper procedures to follow for any involvement of the worker in the use, storage, handling or disposal of the product and the proper use of personal protective equipment. The answer must reflect adequate workplace control of the hazard by engineering or administrative means.

What do you do in case of an emergency?

The answer must show the worker's understanding of procedures to follow in the event of spill, release, fire or poisoning involving the controlled product, and include the use of personal protective equipment where applicable.

Where can you get further hazard information?

This question focuses on the worker's ability to access the significant information provided on labels and data sheets. Workers must know about the supplier label, workplace label and other means of identification applicable to the use of the product and must know the means of being able to obtain information significant to his/her health and safety from the MSDS.

G5.8-1 Supplier label (adopted from WHMIS Bulletin #2)

Effective August 1, 1999

Sections 13(b) and 14(b) of the Hazardous Products Act(HPA) require suppliers to fix labels to controlled products. Section 5.8(1) of the OHS Regulation states "An employer must ensure that the container of a controlled product or a controlled product received at a workplace is labelled with a supplier label". Subsection (3) provides that "If a label applied to a controlled product or a container of a controlled product becomes illegible or is accidentally removed from the controlled product or the container, the employer must replace the label with either a supplier label or a workplace label."

G5.8-2 Labelling on leased or rented chemical application units (adopted from WHMIS Bulletin #2)

Effective August 1, 1999

What are the suppliers' responsibilities to provide labelling on an application unit such as a solvent spray parts washer in the circumstance where the unit is leased or rented to an employer and the supplier, as a condition of the agreement, periodically empties the holding tank on the unit and recharges it with a controlled product?

The unit does not qualify for the manufactured article exemption because workers are likely to be exposed to controlled product during normal conditions of use. Under the Hazardous Products Act, the term "sale" is considered to include rental or leasing. The supplier is obligated to provide and apply a supplier label on the unit. If the label becomes illegible the employer must provide and apply a workplace label or a supplier label as required by section 5.8(3) of the OHS Regulation. He or she should contact the supplier to see if the supplier can provide a new supplier label at the earliest opportunity, for example, when the unit is recharged.

G5.8-3 Multi-container shipments of laboratory samples

Effective August 1, 1999

Sections 14 and 16 of the Controlled Products Regulations contain provisions governing the use of several containers and laboratory samples.

For multi-container shipments of laboratory samples to an outside laboratory the supplier and employer will be considered to meet the intent of legislation with the following procedures.

  • The supplier ensures the outer container bears a WHMIS supplier label. The label must provide, in addition to other required information items, the identity of all hazardous ingredients known or suspected to be contained in the enclosed samples.

  • The supplier ensures the container is provided with a lab analysis requisition form or equivalent which describes which inner containers contain (or are suspected to contain) controlled products. (Note: if a requisition form does not call for analysis of the controlled product in question, specific information on the ingredient must still be provided. Example: a blood sample submitted for a white cell count from a patient infected with hepatitis must be accompanied by information on the microorganism.)

  • The supplier and employer establish an agreement in writing which covers the above two points and provides the employer's assurance that:
    • neither the samples nor any supplier information will be removed from the outer container prior to physical receipt by the lab department within the organization which receives shipment, and
    • an information system is established in the lab, which ensures that each lab worker who could be exposed to a controlled product in any inner container knows the information, which would otherwise be required on a WHMIS label applied to the inner container. (This could be accomplished, for example, by instruction of the worker in the supplier identifier and emergency number combined with a means of identifying the specific hazardous ingredient in the lab sample.)
G5.14-1 Supplier material safety data sheet (MSDS)

Effective August 1, 1999

Section 13(a) and 14(a) of the Hazardous Products Act require a supplier to provide a MSDS with controlled products. Section 5.14(1) of the OHS Regulation states "An employer who acquires a controlled product for use at a workplace must obtain a supplier MSDS for that controlled product if the supplier is required to prepare an MSDS". Section 5.14(2) states "When a supplier MSDS obtained under subsection (1) for a controlled product is 3 years old, the employer must, if possible, obtain from the supplier an up-to-date supplier MSDS for the controlled product if any of the product remains in the workplace".

G5.14-2 Fees (adopted from WHMIS Bulletin #3)

Effective August 1, 1999

Can suppliers charge a fee for a material safety data sheet either as a direct fee or in the form of shipping/handling expense?

If, under section 13(a) or 14(a) of the Hazardous Products Act, a supplier is required to provide a MSDS as a condition of sale or importation to a workplace, a supplier may not charge the purchaser a fee for the MSDS. This applies to the MSDS sent out with first shipment or where an employer requests an updated MSDS, in conformity with section 5.14(2) of the OHS Regulation. However, where an employer is required to obtain an MSDS for a controlled product purchased prior to a supplier compliance point, legislation does not prohibit the supplier from charging a fee for an MSDS. In addition a fee may be legally charged where a supplier provides an MSDS to an employer for product partially or completely exempt from WHMIS pursuant to section 12 of the Hazardous Products Act (for example, pesticides or restricted products being sold as consumer products). However, the Board does not condone the practice of charging fees for MSDS in any circumstance. All instances of fees for MSDS are to be brought to the attention of the WHMIS Coordinator.

G5.15 Laboratory MSDS (adopted from WHMIS Bulletin #7)

Effective August 1, 1999

Section 5.15(2) of the OHS Regulation states "For the purpose of subsection (1), "produces" does not include the escape of a controlled product from equipment or from another product nor does it include intermediate products undergoing reaction within a reaction or process vessel".

What are the circumstances in which a MSDS will be required for products produced and used by the employer in laboratories?

  • Products produced for immediate use in a reaction (or which are produced and consumed in a reaction) do not require production of an MSDS. Such products must be used immediately, be used in total and be consumed entirely during the reaction.
  • A MSDS must be available as required by legislation on all controlled products which are components of mixtures produced in laboratories.
  • For mixtures other than those intended for immediate use, a new MSDS for the mixture must be produced if either:
  • >
    • the hazard of the mixture is different from the hazard of the ingredients separately, or
    • the precautionary information reported on the MSDSs for ingredients is in conflict (for example, a different type of protective gloves or respiratory protection is recommended.)

As such, a new MSDS will not be required for dilutions with water and mixtures in which hazards and precautions are generally unchanged from those of the ingredients.

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Guidelines Part 5 - Containers and storage

G5.22 Covers

Effective August 1, 1999; Editorial Revision August 2004

If an open container of a hazardous substance (as defined in section 106 of the Workers' Compensation Act) could pose a hazard, section 5.22 of the OHS Regulation provides that the container must be kept sealed or covered, when not in use. To determine if a hazard is present, an assessment should be conducted, which takes into consideration the substance's chemical properties, such as flammability, stability, reactivity, incompatibility, corrosivity, volatility, and physical properties, such as physical state (liquid vs. solid), boiling point and/or freezing point. The container's stability should be considered (see section 5.25 of the OHS Regulation and OHS Guideline 5.25), as well as the volume of the material relative to the room space. To evaluate compliance with this section, a hazard assessment is required.

In general, the following substances should always be covered when not in use: flammable solvents; oxidizing agents; reducing agents; strong acids and caustics; and volatile, toxic solvents. Combustible liquids should be covered when there is a possibility of an ignition source in the vicinity.

G5.25 Storage practices

Effective August 1, 1999

Section 5.25 of the OHS Regulation requires that a hazardous substance be stored "in a designated area, in a manner which ensures that it will not readily fall, become dislodged, suffer damage, or be exposed to conditions of extreme temperature." The term "suffer damage" includes damage to the substance resulting from chemical instability such as peroxidation, as well as exposure to light, shock or vibration. Under section 5.24, incompatible substances must not stored "in a manner that would allow them to mix in the event of container leakage, breakage or other such circumstance." For information on chemical stability and incompatibilities, the appropriate material safety data sheet should be referenced.

The general training and work procedure requirements of section 5.2(d) of the OHS Regulation also apply.

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Guidelines Part 5 - Flammable and combustible substances

G5.30 Dispensing

Effective August 1, 1999

A flammable liquid storage room for dispensing or transferring a flammable liquid must be designed in accordance with section 5.30 of the OHS Regulation. Permitted quantities of combustible or flammable liquids that may be stored outside of an approved storage cabinet, room or area are specified in section 5.33. The definitions of "approved storage area", "approved storage cabinet" and "approved storage room" are provided in section 5.1.

This section applies to approved storage rooms, cabinets or areas, as defined under section 5.1. It does not apply to physically separated storage sheds, such as a small fuel shed.

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Guidelines Part 5 - Substances under pressure

G5.38 Handling and securing containers

Effective August 1, 1999

Section 5.38(2) of the OHS Regulation requires that a compressed gas cylinder be secured to prevent falling or rolling during storage, transportation and use. Where practicable, the cylinder must be kept in the upright position.

Compliance with this section can be achieved either by

  • chaining the cylinders to a secure object (a method typically used by welding shops, machine shops, and other employers handling cylinders in relatively small numbers) or,
  • by using the "interlock" method of storing cylinders (a method used by gas manufacturers, distributors, transfill depots, subdivisions and company depots, or other member companies of the Compressed Gas Association.)

As shown in the Figure below (this is an overhead or "bird's eye" view), the interlock method consists of dovetailing the cylinders into a cohesive unit. This method is acceptable when cylinders are in an area shipping or receiving a large number of cylinders.

Cylinder Storage
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Guidelines Part 5 - Controlling exposure

G5.48-1 Table of exposure limits - background information

Issued October 29, 2003; Revised February 11, 2004; Revised February 4, 2005

Section 5.48 of the OHS Regulation ("Regulation") states:

Except as otherwise determined by the board, the employer must ensure that no worker is exposed to a substance that exceeds the ceiling limit, short-term exposure limit, or 8-hour TWA limit prescribed by ACGIH.

Section 5.1 of the OHS Regulation defines ACGIH:

"ACGIH" means the American Conference of Governmental Industrial Hygienists publication entitled "Threshold Limit Values and Biological Exposure Indices", dated 2002, as amended from time to time.

This guideline provides information on the significance of exposure limits for chemical and biological substances and the sources for those limits. It includes a link to the table of exposure limits established under section 5.48 of the OHS Regulation.

An exposure limit is a maximum allowed airborne concentration and is not intended to represent a fine line between safe and harmful conditions. In determining an exposure limit, it is not possible to take into account all factors that could influence the effect that exposure to the substance may have on an individual worker. Therefore, for all hazardous substances, regardless of any assigned exposure limit, the guiding principle is elimination of exposure or reduction to the lowest level that is reasonably achievable below the exposure limit.

Due to a wide variation in individual susceptibility, some workers may experience discomfort from some substances at concentrations at or below the exposure limit. Others may be affected more seriously by aggravation of a pre-existing condition, or by development of an occupational disease. Furthermore, other workplace contaminants may affect an individual's response. The effects of combined chemical exposures are often unknown or poorly defined.

The exposure limits adopted under section 5.48 are based on both ACGIH TLVs and Board policy. Substances covered by Board policy are of three broad types:

  • Those substances, previously listed in Table 5-4 of the OHS Regulation, that have lower exposure limits than the corresponding TLV in the ACGIH table called "Adopted Values" in Threshold Limit Values and Biological Exposure Indices.
  • Those substances for which a TLV is currently not considered feasible for B.C. workplaces. This exception is limited to formaldehyde, styrene, and wood dust (all forms).
  • Those substances, previously listed in Table 5-4 of the OHS Regulation, that are not currently listed in the ACGIH table of Adopted Values.

For the convenience of users, this guideline links to the Table of Exposure Limits for Chemical and Biological Substances, which lists all exposure limits for chemical and biological substances that are regulated by the WCB, whether the limits are based on ACGIH tables or Board policy.

Information is also available by contacting your local WCB office or calling 604 276-3100 or toll-free 1 888 621-7233.

G5.48-2 Annual revisions to exposure limits

Issued October 29, 2003; Revised February 11, 2004; Revised February 4, 2005; Revised April 29, 2005

Section 5.48 of the OHS Regulation states:

Except as otherwise determined by the Board, the employer must ensure that no worker is exposed to a substance that exceeds the ceiling limit, short-term exposure limit, or 8-hour TWA limit prescribed by ACGIH.

Section 5.1 of the OHS Regulation defines ACGIH:

"ACGIH" means the American Conference of Governmental Industrial Hygienists publication entitled "Threshold Limit Values and Biological Exposure Indices", dated 2002, as amended from time to time.

This guideline outlines the means the WCB has established for addressing responsibilities for exposure limits under the phrasing in section 5.48, "Except as otherwise determined by the Board."

The ACGIH conducts an ongoing scientific review of chemical substances with the purpose of confirming existing Threshold Limit Values (TLVs) or proposing any revisions. Information on updates to TLVs are covered in the "Notice of Intended Changes" (NIC) table in the ACGIH TLV booklet. Annually, the ACGIH reviews the NIC and adopts changes to TLVs it considers appropriate.

The ACGIH issues TLVs only as recommendations for occupational hygiene practice, not as legal exposure limits. As a regulatory authority in BC, the WCB adopts legal exposure limits, as established in s. 5.48, based on ACGIH TLVs but subject to any modification it may deem necessary.

The WCB has established the Occupational Exposure Limit Review Committee (the Committee), which has responsibilities to the Board of Directors (the BOD) for making recommendations on exposure limits, under its terms of reference, which can be found on the WCB web site at www.worksafebc.com.

Any proposed recommendations of the Committee are subject to a consultation process before being presented to the BOD, and the BOD is advised of the results of such consultation.

The Committee will review and consider the results of stakeholder consultation before finalized recommendations are forwarded to the BOD for decision.

If a decision is made by the BOD to make an exception for a substance of concern, a public hearing will be facilitated to determine whether the exception should be maintained.

Any decisions by the BOD to establish limits other than those based on ACGIH are recorded in Board policy, and are also entered into the Table of Exposure Limits for Chemical and Biological Substances. Both documents are found on the WCB web site.

G5.48-3 Normal 8-hour work period

Issued originally as G5.48-2 August 1, 1999; Revised October 29, 2003

Section 5.48 of the Occupational Health and Safety Regulation states:

Except as otherwise determined by the board, the employer must ensure that no worker is exposed to a substance that exceeds the ceiling limit, short-term exposure limit, or 8-hour TWA limit prescribed by ACGIH.

Section 5.1 of the OHS Regulation defines "8-hour TWA limit":

"8-hour TWA limit" means the time weighted average (TWA) concentration of a substance in air which may not be exceeded over a normal 8 hour work period.

For an 8-hour TWA, a normal 8-hour work period will generally refer to a routine shift length of no more than 8 hours, over which exposure to an air contaminant occurs. In computing the TWA, breaks should be included if there is significant exposure during the breaks but not otherwise. For example, in the case of a routine shift length of 8 hours with an additional half-hour or three quarter-hour lunch break, the 8-hour work period is the TWA period, if there is no significant exposure over the lunch break. If significant exposure occurs during the lunch break, then the work period should be considered more than 8 hours and the exposure reduction factors stipulated in section 5.50 need to be applied. Note that 15-minute paid breaks (such as coffee breaks) should be included in the exposure period.

Refer to OHS Guideline G5.50 for assistance in applying the reduction factors.

G5.48-4 Conversions for ppm and mg/m3

Issued originally as G5.48-3 August 1, 1999; Revised February 11, 2004

Section 5.48 of the Occupational Health and Safety Regulation states:

Except as otherwise determined by the board, the employer must ensure that no worker is exposed to a substance that exceeds the ceiling limit, short-term exposure limit, or 8-hour TWA limit prescribed by ACGIH.

The ACGIH's Threshold Limit Values and Biological Exposure Indices provides instructions for converting the exposure limit (8-hour TWA limit or STEL or ceiling) for gases and vapours from parts per million (ppm) to milligrams per cubic metre (mg/m3). This might be used in situations where a substance in measured or listed in milligrams per cubic metre and the Table of Exposure Limits for Chemical and Biological Substances lists that substance in parts per million.

Exposure limit in mg/m3 = (limit value in ppm)(gram molecular weight of substance)
24.45

Conversely, the formula for converting a known exposure limit in mg/m3 to the equivalent exposure limit in ppm is:

Exposure limit in ppm = (24.45)(limit value in mg/m3)
gram molecular weight of substance

Gram molecular weight values are shown in the column labelled "MW" in the Table of Exposure Limits for Chemical and Biological Substances. The numeric value of 24.45 in both formulae is the molar volume of air in litres at normal temperature and pressure (NTP), which is considered to be 25ºC and 1 atmosphere (101.325 kPa or 760 mm Hg or 760 torr). Note that this is not the same as standard temperature and pressure (STP), which is 0ºC and 1 atmosphere.

If you are not dealing with measurements at NTP then you may need to calculate the molar volume of air for a temperature and pressure other than NTP and substitute this calculation for 24.45. Methods for calculating molar volumes can be found in standard occupational hygiene reference books such as those listed in OHS Guideline G5.53-4.

G5.48-5 Welding fume

Issued originally as G5.48-4 August 1, 1999; Revised February 11, 2004; Revised August 3, 2006

Regulatory excerpt
Section 5.48 of the OHS Regulation states:

Except as otherwise determined by the board, the employer must ensure that no worker is exposed to a substance that exceeds the ceiling limit, short-term exposure limit, or 8-hour TWA limit prescribed by ACGIH.

(TWA refers to time-weighted average, and ACGIH refers to American Conference of Governmental Industrial Hygienists.)

Purpose of guideline
This guideline explains that welding fumes are of variable composition and provides information on substances that may be present. It also discusses the sources of information on welding fumes and how to determine applicable exposure limits. The term "welding" includes thermal cutting and allied processes such as brazing.

Welding fume composition
Establishing a worker's exposure to hazardous substances in welding fumes is not a simple matter since this depends on the material being welded as well as the process and electrodes used. Welding fumes may contain fluoride, and metals or oxides of metals such as aluminum, antimony, arsenic, barium, beryllium, cadmium, chromium, hexavalent chromium, cobalt, copper, iron, lead, manganese, nickel, silver, tin, titanium, vanadium and zinc.

Apart from welding fumes, hazardous levels of gases, including carbon monoxide, oxides of nitrogen, or ozone may also be present during welding. In addition, there may be a risk of asphyxiation when shielding gases such as argon are used, particularly in an enclosed or confined space. Decomposition products such as phosgene can form when coatings or residues on or near the object being welded are heated.

Sources of information on welding fumes
To determine the potential level of exposure to welding fumes, a systematic review of the base metal, electrode, and type of process is required. Information requirements for hazardous materials covered by WHMIS are found in sections 5.3-5.19 of the OHS Regulation, and for all substances, in section 5.2. The material safety data sheets (MSDS) or other applicable information sources should be used to identify hazardous ingredients and expected products of reaction and decomposition. Information on electrodes, the metal(s) being welded or cut, and the specific type of welding process should also be identified.

Exposure limits
Once the information on possible types of exposure has been determined, the Table of Exposure Limits for Chemical and Biological Substances should be consulted for the applicable exposure limit(s).

The employer must comply with the exposure limit for each of the individual constituents in the welding fume. An additive exposure limit as established in section 5.51 may apply if two or more of these hazardous substances demonstrate similar toxicological effects. See OHS Guideline G5.51 for further information.

(Note that sections 12.115 (Coatings on metals) and 12.117 (Silver solder) of the OHS Regulation address issues respectively of coatings on metals, and cadmium in silver solder.)

G5.48-6 Allergenic species of wood dust

Issued originally as G5.48-5 August 1, 1999; Revised February 11, 2004

Section 5.48 of the Occupational Health and Safety Regulation states:

Except as otherwise determined by the board, the employer must ensure that no worker is exposed to a substance that exceeds the ceiling limit, short-term exposure limit, or 8-hour TWA limit prescribed by ACGIH.

The Table of Exceptions in Policy Item R5.48-1 of the Prevention Manual includes a listing for wood dust, all allergenic species. (As noted in OHS Guideline G5.48-1, substances with exposure limits that are not the current ACGIH TLVs are listed in the Table of Exceptions in this policy. They are included in the Table of Exposure Limits for Chemical and Biological Substances and indicated with an asterisk.) For the purposes of Policy Item R5.48-1, the following species should be considered allergenic for the purposes of "wood dust -- allergenic species". This list is derived from Chan-Yeung, M, Malo, J-L, "Aetological Agents in Occupational Asthma," European Respiratory Journal, Volume 7, 1994 (pp. 346-371).

Wood Species Considered to be Allergenic

Common nameSpecies name
Softwood 
Western red cedarThuja plicata
California redwoodSequoia sempervirens
Cedar of LebanonCedra libani
Eastern white cedarThuja occidentalis
  
Hardwood 
Oak, EuropeanQuercus robur
BeechFagus spp.
Ash 
 Fraxinus americanum
Tropical Wood 
AbirucanaPouteri
African mapleTriplochiton scleroxylon
African zebraMicroberlinia
CabreuvaMyrocarpus fastigiatus
Central American walnutJuglans olanchana
CocabollaDalbergia retusa
Common name unavailableTanganyika aningre
Ebony, AfricanDiospyros crassiflora
Iroko or KambalaChlorophora excelsa
FenamboukCaesalpinea echinata
KejaatPterocarpus angolensis
Kobite Nesorgordonia papaverifera
Mahogany, AfricanKhaya spp.
MakoreTieghemella hecklii
Quillaja barkSpecies name unavailable
Pau MarfimBalfourodendron riedelianum
RaminGonystylus bancanus
G5.48-7 Nuisance dusts

Issued August 16, 2000; Revised February 11, 2004; Revised November 23, 2005

Regulatory excerpt
Section 5.48 of the Occupational Health and Safety Regulation states:

Except as otherwise determined by the board, the employer must ensure that no worker is exposed to a substance that exceeds the ceiling limit, short-term exposure limit, or 8-hour TWA limit prescribed by ACGIH.

(TWA refers to time-weighted average, and ACGIH refers to American Conference of Governmental Industrial Hygienists.)

Purpose of guideline
The term "nuisance dust" has been used for years to describe a group of dusts with similar effects on people. Nuisance dusts are insoluble or poorly soluble in water and do not cause toxic effects on humans other than by inflammation of the respiratory tract or by accumulation of material in the lung (lung overload).

Exposure limits for nuisance dusts involve additional terms such as "total dust," "respirable dust," and "Particles not otherwise classified PNOC)." This guideline explains the use of these terms. It also provides information on the exposure limits for PNOC and various nuisance dusts.

In addition, the guideline provides some technical information on a relatively new term that has begun to be used to describe dusts - "inhalable" particulate.

Total and respirable dusts
Historically, particulates in the air have been measured as "total dust." This term refers to dusts with a wide range of particle sizes capable of being deposited in the various regions of the human respiratory tract, from the nose and throat down into the gas exchange area of the lung.

Dusts have also been measured as "respirable dusts," which refers to the portion of total dust that is capable of passing through the upper respiratory tract and then being deposited in the gas exchange area of the lung.

Many nuisance dusts have an 8-hour TWA exposure limit of 10 mg/m3 for total dust, as shown in the Table of Exposure Limits for Chemical and Biological Substances (the Table). Examples include aluminum oxide, calcium sulfate, cellulose, emery, gypsum and Portland cement.

Such substances also have an 8-hour TWA of 3 mg/m3 for the respirable fraction of the dust. These substances are flagged in the Table with an End Note (N) which explains that an exposure limit based on the respirable fraction also applies.

PNOC (Particles not otherwise classified)
PNOC are nuisance dusts that have not been assigned individual occupational exposure limits. PNOC may arise in various circumstances, for example, some roadwork operations, grinding acrylics and buffing nails. PNOCs are assigned a TWA of 10 mg/m3 for the total dust, and a TWA of 3 mg/m3 for the respirable fraction.

Additional technical information - Inhalable particulate
Exposure limits adopted by WorkSafeBC are based in part on the threshold limit values of the ACGIH. The concept of "inhalable dust," which has been developed by the ACGIH, refers to dusts that can be deposited anywhere in the respiratory tract. Although it is similar to the concept of "total dust," it is considered to more accurately describe the range of particle sizes that are deposited.

Substances that have been reviewed by the ACGIH, and for which exposure limits based on "inhalable" dust have been adopted by WorkSafeBC, include magnesium oxide, molybdenum (metal and insolubles), and silicon carbide (non-fibrous). Over time, the ACGIH will continue to review the application of "inhalable" to other substances. As changes are adopted by WorkSafeBC they will be reported in the Table of Exposure Limits for Chemical and Biological Substances.

G5.48-8 Simple asphyxiants -- Inert gases or vapours

Issued October 29, 2003; Revised February 11, 2004

Section 5.48 of the Occupational Health and Safety Regulation states:

Except as otherwise determined by the board, the employer must ensure that no worker is exposed to a substance that exceeds the ceiling limit, short-term exposure limit, or 8-hour TWA limit prescribed by ACGIH.

A number of gases and vapours, such as acetylene, argon, and nitrogen, when present in high concentrations in air, act primarily as simple asphyxiants without other significant physiological effects. (A simple asphyxiant is a substance that can displace oxygen in the air, resulting in suffocation from lack of oxygen.) The ACGIH does not assign a TLV, or exposure limit, because the limiting factor is the available oxygen in air, not the toxic nature of the substance itself. These substances are identified as "simple asphyxiants" in the STEL column of theTable of Exposure Limits for Chemical and Biological Substances.

An oxygen-deficient atmosphere is defined in section 1.1 of the OHS Regulation as air with less than 19.5% oxygen by volume, or where the partial pressure of oxygen is less than 16.3 kPA (122 mm Hg). Oxygen-deficient atmospheres do not provide adequate warning, and most asphyxiants are odourless. Note that several of the simple asphyxiants are highly flammable and can present explosion hazards, and under section 5.31 of the OHS Regulation employers must take account of this factor in limiting the concentration of the asphyxiant. Also note that the requirements of sections 5.27, 5.31 and 5.56 of the OHS Regulation apply.

G5.48-9 Measuring compliance with the exposure limits

Issued originally as G5.48-6, August 1, 1999; revised October 29, 2003

Section 5.48 of the Occupational Health and Safety Regulation states:

Except as otherwise determined by the board, the employer must ensure that no worker is exposed to a substance that exceeds the ceiling limit, short-term exposure limit, or 8-hour TWA limit prescribed by ACGIH.

The following information outlines the protocol for officers in establishing compliance with this section, and is based largely on operating procedures practiced by Board prevention officers over the last 25-30 years. These follow recognized occupational hygiene principles. For further guidance on walkthrough surveys, exposure monitoring and evaluation of the exposure monitoring program, refer to OHS Guidelines G5.53-1 to G5.53-3.

Officers will not normally perform sampling if the employer has an acceptable workplace monitoring program in place, indicating that exposures are within the applicable exposure limits. In addition, officers will normally not sample for compliance purposes during temporary or emergency conditions, where exposures may be higher than normal. Officers may elect to conduct air sampling if they suspect that a problem exists and the employer has failed to conduct an exposure assessment or has an inadequate exposure-monitoring program. Additional circumstances under which an officer may be required to sample are outlined in OHS Guidelines G5.53-1 to G5.53-3.

Typically, the officer will select the worker or workers with the highest suspected exposures and conduct sampling during worst-case scenarios, such as during periods when activities or activity levels expected to result in the highest exposure are underway. In accordance with established occupational hygiene principles, compliance with exposure limits is determined by comparing the 95% upper and lower confidence limits of the mean exposure of a similarly exposed group to the exposure limit. The 95% upper and lower confidence limits represent a range of reasonable values that are intended to contain the average exposure level with 95% confidence. That is, one can be 95% confident that the upper and lower confidence limits will cover the mean exposure.

If only one sample is collected, sampling and analytical error must be accounted for. Use the coefficient of variation specified for the sampling method and follow the confidence limit guideline as described below. Contact the Occupational Disease Prevention Services section for information regarding the coefficient of variation for the analytical method of interest.

Formulae for calculating the upper and lower confidence limits can be found in standard occupational hygiene references. Three references that are acceptable to the Board are listed in OHS Guideline G5.53-4.

The guidelines for compliance with the exposure limits using the 95% confidence limits are outlined below.

  • If the average exposure does not exceed the exposure limit and the upper confidence limit (UCL) is less than the exposure limit, then there is more than 95% confidence that the employer is in compliance.
  • If the average exposure is greater than the exposure limit and the lower confidence limit (LCL) is also greater than the exposure limit, then there is more than 95% confidence that the employer is in non-compliance.
  • If the average exposure does not exceed the exposure limit, but the upper confidence limit exceeds the exposure limit, there is not 95% confidence that the employer is in compliance. Similarly, if the measured exposure exceeds the exposure limit, but the lower confidence limit is below the exposure limit, there is not 95% confidence that the employer is in non-compliance. For both of these situations, there is a "possible over-exposure." Note that the closer the lower confidence limit comes to exceeding the exposure limit, the more probable it becomes that the results are not in compliance. To more definitely determine whether the exposure levels are within compliance, further sampling is needed.

An officer may elect to sample on the employer's behalf or may require the employer to conduct the sampling under the provisions of section 5.53 of the OHS Regulation. Refer to OHS Guidelines G5.53-1 to G5.53-3 for further information.

Guidelines for compliance are shown schematically in the figure below.

Determining Compliance with Occupational Exposure LImits (OEL's)

G5.48-10 Use of indicator tubes to measure compliance

Issued originally August 1, 1999; Revised February 11, 2004

Section 5.48 of the Occupational Health and Safety Regulation states:

Except as otherwise determined by the board, the employer must ensure that no worker is exposed to a substance that exceeds the ceiling limit, short-term exposure limit, or 8-hour TWA limit prescribed by ACGIH.

Colourimetric indicator tubes are useful for assessing worker exposure. However, these devices are limited with regard to applicability, specificity, and accuracy. Their primary intention is for screening exposures and the user must be familiar with these critical limitations if proper judgements are to be made, particularly in the matter of assessing compliance. Indicator tubes should meet the criteria established by Title 42 CFR Part 84 of the U.S. Code of Federal Regulations. An independent testing agency, Safety Equipment Institute (SEI) took over the task of product testing from NIOSH in 1985. The SEI certifies a manufacturer's indicator tube if it meets the minimum requirement set out in the standard, as follows:
± 35% accuracy at one-half the exposure limit, and
± 25% at one to five times the exposure limit.

Adherence to a quality assurance plan is verified by testing samples obtained from the supplier. Contact the Occupational Disease Prevention Services section for further information.

In essence this means that one should read an indicator tube ±25% of the indicated reading if the exposure level is in the vicinity of the exposure limit unless several grab samples are taken to increase the statistical confidence, in accordance with acceptable occupational hygiene statistical practice. Indicator tubes can be used to measure non-compliance with either short-term exposure limits or ceiling limits. In the case of a single grab sample by detector tube, if the reading exceeds either the short-term exposure limit or the ceiling limit by 25%, there is sufficient evidence of non-compliance with the exposure limit. If the indicator tube reading is close to the short-term exposure limit or ceiling limit (within 25±% of the limit), and if it appears that an overexposure may exist, other more reliable sampling methods should be used before a decision is made. See also OHS Guideline G5.48-9 for guidelines on determining whether there is compliance with the exposure limits.

Readings from a short-term indicator tube should be compared to the appropriate short-term exposure limits in the Table of Exposure Limits for Chemical and Biological Substances (such as a short-term exposure limit or a ceiling limit). They should not be compared to 8-hour TWA limits. In addition, 8-hour time-weighted averages must not be calculated from results obtained using short-term indicator tubes.

Long-term indicator tubes connected to a sampling pump may be used to determine 8-hour time-weighted averages. These averages are then compared to the appropriate 8-hour TWA limit in the Table of Exposure Limits for Chemical and Biological Substances.

See OHS Guideline G5.48-1 for the Table of Exposure Limits for Chemical and Biological Substances.

G5.49 Application of excursion limits

Issued January 1, 2007

Regulatory excerpt
Section 5.1 of the OHS Regulation ("Regulation") contains the following relevant definitions:

"ACGIH" means the American Conference of Governmental Industrial Hygienists publication entitled "Threshold Limit Values and Biological Exposure Indices", dated 2002, as amended from time to time;

"8-hour TWA limit" means the time weighted average (TWA) concentration of a substance in air which may not be exceeded over a normal 8 hour work period;

"short-term exposure limit" or "STEL" means the time weighted average (TWA) concentration of a substance in air which may not be exceeded over any 15 minute period, limited to no more than 4 such periods in an 8-hour work shift with at least one hour between any 2 successive 15 minute excursion periods;

"ceiling limit" means the concentration of a substance in air which may not be exceeded at any time during the work period;

Section 5.48 of the Regulation states:

Except as otherwise determined by the Board, the employer must ensure that no worker is exposed to a substance that exceeds the ceiling limit, short-term exposure limit, or 8-hour TWA limit prescribed by ACGIH.

Section 5.49 of the Regulation states:

If a substance referred to under section 5.48 is provided only with an 8-hour TWA limit, the employer must, in addition to the requirement of section 5.48, ensure that a worker's exposure to the substance does not exceed

(a) three times the 8-hour TWA limit for more than a total of 30 minutes during the work period, and

(b) five times the 8-hour TWA limit at any time.

Section 5.50(1) of the Regulation states:

If the work period is more than 8 hours in a 24 hour day, the 8-hour TWA limit must be reduced by multiplying the TWA limit by the following factors:

FactorLength of work period (in hours)
0.7More than 8, but not more than 10
0.5More than 10, but not more than 12
0.25More than 12, but not more than 16
0.1More than 16

Purpose of guideline
The purpose of this guideline is to explain, and provide examples of the application of excursion limits in section 5.49.

Background Information
Threshold Limit Values (TLVs) refer to airborne concentrations of chemical substances and represent conditions under which it is believed that nearly all workers may be repeatedly exposed, day after day, over a working lifetime, without adverse health effects. There are three categories of TLVs: time-weighted average ("TWA") over an 8-hour period; short-term exposure limit ("STEL"), and a ceiling limit. Some chemical substances have been assigned values for a TWA and either a STEL or a ceiling limit, while other substances have been assigned TWA or ceiling limits only. (See also OHS Guidelines G5.48-1 to G5.48-4 for general information on exposure limits).

Section 5.49 of the Regulation establishes excursion limits for hazardous substances which have only been assigned a TWA by applying a formula to the assigned 8-hour TWA value. The purpose of excursion limits is to ensure workers are not exposed to excessively high short bursts of hazardous substances which could cause acute health effects.

Excursion limits are based on the premise that the maximum excursion should be related to the variability generally observed in actual industrial processes. Research has shown that if the variation of short-term exposure values is very high (greater than three times the average), it is an indication that the process is not under good control.

In order to be assured of satisfactory control of the industrial process and associated exposure values, a factor of three times the TWA is used. This ensures that only a small percentage of exposure values will exceed this value. If this excursion limit is exceeded, there is a high likelihood that further control measures are required.

Excursion limits apply only when neither a STEL nor ceiling value has otherwise been assigned to the substance. Section 5.49 is not meant to supersede any assigned STEL or ceiling limit.

Examples of Application of Excursion Limits
Elemental mercury has a TWA of 0.025 mg/m3 (No STEL or Ceiling limit)
The principle of excursion limits applies in this case since there is only a TWA for this substance. As per section 5.49(a), an employer must ensure that a worker's exposure to elemental mercury does not exceed 0.075 mg/m3 for more than a total of 30 minutes during the work period.

A worker exposed to a concentration of 0.080 mg/m3 for 15 minutes and to 0.060 mg/m3 for 15 minutes, is exposed, on average, to 0.070 mg/m3. This average value is less than 0.075 mg/m3 and is therefore in compliance with section 5.49(a).

As per section 5.49(b), the employer also must ensure that a worker's exposure to elemental mercury does not exceed 0.125 mg/m3 at any time during the work period. For example, a direct reading measurement of 0.15 mg/m3, taken with a calibrated mercury monitor, is a determination of non-compliance.

Acetic acid has a TWA of 10 ppm and a STEL of 15 ppm
The principle of excursion limits does not apply in this case because there is a STEL assigned for acetic acid. A worker is protected by the 8-hour TWA and is protected from high short burst exposures of acetic acid by the 15 minute STEL.

Chloroacetone has a ceiling limit of 1 ppm (No TWA or STEL)
The principle of excursion limits does not apply in this case because there is a ceiling limit assigned for chloroacetone. A worker is protected by setting a maximum permissible concentration in air, which must not be exceeded at any time during the work period.

Ethylene Oxide has a TWA of 0.1 ppm and a STEL of 1 ppm
The principle of excursion limits does not apply in this case because there is a STEL assigned for ethylene oxide. A worker is protected by the 8-hour TWA and is protected from high short burst exposures of ethylene oxide acid by the 15 minute STEL. Although there is no ceiling limit for ethylene oxide, the STEL also provides significant protection against very short, momentary high bursts - these bursts must not raise the 15 minute average concentration to higher than the STEL and must be limited to no more than 4 such periods in an 8 hour work shift with at least one hour between any 2 successive 15 minute excursion periods.

Application of Excursion Limits for Extended Work Periods
Section 5.50 of the Regulation and the associated OHS Guideline G5.50 explain how and when the TWA must be reduced for exposures during an extended work period. When the provisions for reduction of the TWA apply, this reduced value is the value to be used for excursion limit calculations in section 5.49.

For example, if a worker is exposed to airborne elemental mercury (8-hour TWA limit of 0.025 mg/m3, no STEL, no ceiling limit) routinely over a 12-hour work shift, then a reduction factor of 0.5 must be applied to the exposure limit, resulting in a reduced TWA limit of 0.0125 mg/m3. This worker must not be exposed to an average of more than (3 X 0.0125 =) 0.0375 mg/m3 for more than a total of 30 minutes during the 12-hour work period. The worker must not be exposed to more than (5 X 0.0125 =) 0.0625 mg/m3 at any time during the 12-hour work period.

G5.50 Extended work periods

Issued August 1, 1999; Revised February 11, 2004

Section 5.50(1) of the Occupational Health and Safety Regulation states:

If the work period is more than 8 hours in a 24 hour day, the 8-hour TWA limit must be reduced by multiplying the TWA limit by the following factors:

FactorLength of work period (in hours)
0.7More than 8, but not more than 10
0.5More than 10, but not more than 12
0.25More than 12, but not more than 16
0.1More than 16

Where the work period exceeds 8 hours in a 24-hour day, the 8-hour TWA limit listed in the Table of Exposure Limits for Chemical and Biological Substances must be modified to ensure that workers on extended shifts are as equally protected as if they were working on conventional 8-hour shifts. Section 5.50(1) of the OHS Regulation provides the factors by which the 8-hour TWA limit must be reduced.

See OHS Guideline G5.48-1 for the Table of Exposure Limits for Chemical and Biological Substances.

Refer to OHS Guideline G5.48-3 for clarification of "normal" 8-hour shift.

This section envisages several consecutive workdays with shifts longer than the normal 8-hour shift, not an occasional overtime shift. If exposure occurs as a single event lasting less than 8 hours during a work shift and there is a recovery period of at least 16 hours (at work or otherwise) before any further exposure, the reduction factor would not normally apply.

G5.51 Additive effects

Issued August 1, 1999; Revised October 29, 2003

Section 5.51 of the Occupational Health and Safety Regulation states:

If there is exposure to a mixture of 2 or more substances with established exposure limits which exhibit similar toxicological effects, the effects of such exposure must be considered additive unless it is known otherwise, and the additive exposure must not exceed 100% when calculated as follows:
    AE = %EL1 + %EL1 + ... %ELn
where
    (a) AE is the calculated additive exposure to the mixture,
    (b) %EL1 is the measured exposure to component 1 of the mixture expressed as a percentage of its exposure limit,
    (c) %EL2 is the measured exposure to component 2 of the mixture expressed as a percentage of its exposure limit, and
    (d) %ELn is the measured exposure to any additional components of the mixture expressed as a percentage of their respective exposure limits.

That is, if the sum derived from the equation exceeds 100%, the exposure limit of the mixture is considered as being exceeded.

This section applies to all exposure limits, with the exception of excursion limits (section 5.49), as they are not considered to be "established exposure limits." When considering additive effects, similar exposure limits must be compared (for example 8-hour TWA limits must be compared with 8-hour TWA limits; do not compare an 8-hour TWA limit and a STEL).

For effects to be considered additive, the substances must act upon the same target organ (such as the kidneys) or target organ system (such as the respiratory system) and have similar toxicological effects. Thus, substances with primarily acute effects would not be considered additive with substances which cause chronic effects, even if same organ or organ system was involved. For example, although both silica and ammonia affect the lungs, they would not be considered additive because exposure to silica causes a chronic condition (silicosis), while exposure to ammonia causes acute effects (respiratory tract irritation).

Some examples of processes where additive effects need to be considered are welding, painting, and plastics manufacturing. Additive effects should also be taken into account for exposure to diesel exhaust. If it is not clear whether additive effects apply, one should consult an occupational hygienist.

G5.52 Skin notation

Issued August 1999; Revised February 11, 2004

Section 5.52 of the Occupational Health and Safety Regulation states:

If skin absorption may contribute to the overall exposure, effective measures must be taken to limit exposure by this route.

This section applies to those substances listed with a "Skin" notation in the Table of Exposure Limits for Chemical and Biological Substances (see OHS Guideline G5.48-1).

The notation refers to the potential significant contribution to the overall exposure by skin absorption (called the cutaneous route) either by contact with vapours or, of probable greater significance, by direct skin contact with the substance. This includes contact with the mucous membranes of the eyes. Specific substances (vehicles) in solutions or mixtures can also significantly enhance potential skin absorption. Although some substances are capable of causing irritation, dermatitis, and sensitization in workers, these properties are not considered relevant by the ACGIH when assigning a "Skin" notation. However, a dermatological condition can significantly affect the potential for skin absorption.

The "Skin" notation is intended to alert the reader that air sampling alone is insufficient to quantify exposure accurately and that measures to prevent significant skin absorption should be considered. For guidance on measures to control exposure, refer to OHS Guideline G5.55 or consult with an occupational hygienist or occupational physician.

G5.53-1 Workplace monitoring

Effective August 1, 1999

Where a worker is or may be exposed to a hazardous substance, section 5.53 of the OHS Regulation requires an assessment of the potential for harmful exposure and monitoring, or sampling, of exposure levels to airborne contaminants. The program required under Section 5.53 has 3 major elements:

  • a walk-through survey
  • air sampling to assess the potential for overexposure, and
  • workplace monitoring to reliably characterize worker exposure, where workers may be exposed to an air contaminant at levels greater than 50% of the exposure limit. Section 5.53(4) provides that Workplace exposure monitoring and assessment must be conducted using occupational hygiene methods acceptable to the board.

As provided for under section 130(i) of the Workers Compensation Act and section 3.8 of the OHS Regulation, the joint committee should be involved in workplace monitoring, where feasible.

Officers may conduct sampling to determine compliance with both sections 5.48 and 5.53 of the OHS Regulation. Additional circumstances where an officer may be required to conduct workplace monitoring include the following:

  • claims investigations
  • accident investigations
  • investigations conducted under section 3.12(5)
  • dispute resolution
  • asbestos abatement projects and,
  • penalty assessments.

An officer may encounter situations were the employer has neither conducted a walk-through survey nor performed sampling of contaminants, as required. In these circumstances, the officer may elect to either assist the employer in conducting the survey or performing the sampling (as part of an inspection) or require the employer to conduct the survey or perform the sampling. In deciding wherther to assist the employer, the officer may consider

  • the employers resources and abilities to
    • conduct the survey or perform the sampling him- or herself, or
    • engage professional services
  • the educational benefit to the employer of accompanying the officer on a walk-through survey, and
  • the employer's commitment to an occupational health and safety program under the provision of part 3.

Some questions to consider

  • does the firm have appropriate in-house expertise?
  • does the firm have access to technical support from either the parent corporation or a supplier of the harmful substance(s)?
  • are private occupational hygiene services for sampling and/or analytical work readily available in the community?

The manner in which compliance is assessed with each element of the program is described in detail below.

G5.53-2 Assessing compliance -- the walk-through survey

Effective August 1, 1999

Section 5.53(1) of the requires an employer to conduct a walk-through survey if a worker is or may be exposed to a harmful substance. An officer encountering an employer who has not conducted a walk-through survey at a workplace where, in the officer's opinion, workers may be exposed to a harmful substance, will require the employer to conduct the walk-through survey in accordance with this section.

If the employer conducts the walk-through survey and concludes that no worker may be at risk of overexposure to an airborne contaminant, and the officer accepts this conclusion as being reasonable, no further action will be necessary, unless there is a change in work conditions. If, on the other hand, the employer finds a worker potentially at risk of overexposure to an airborne contaminant, air sampling must be considered, as required by section 5.53(2). Depending on the outcome of the sampling, further action may be required under sections 5.53(3), 5.54 and 5.55 of the OHS Regulation.

The officer may determine that workers are at risk based on

  • observations at the worksite (this may be in the course of assisting an employer with a walk-through survey or during an inspection)
  • sampling results from the worksite or similar worksites or operations
  • first aid reports
  • worker complaints.
G5.53-3 Monitoring worker exposure

Issued August 1999; Revised February 11, 2004

Under section 5.53(2) of the OHS Regulation, the employer must conduct air sampling when the walk-through survey required under section 5.53(1) reveals that workers may be at risk of overexposure. The guidelines set out in OHS Guideline G5.48-9 are acceptable to the Board for complying with section 5.53(2). Normally, the employer would select one or more workers for sampling, which should be those workers who are likely to be the most heavily exposed on a given day (worst case conditions). Sampling results are then compared with exposure limits in section 5.48 (Table of Exposure Limits for Chemical and Biological Substances in OHS Guideline G5.48-1) using the guidelines in G5.48-9.

If the assessment conducted under section 5.53(2) reveals that a worker may be exposed to an air contaminant in excess of 50% of its exposure limit, -or measurement is not possible at 50% of the applicable exposure limit, additional workplace monitoring to reliably determine worker exposure is required under section 5.53(3)(a).

"Additional monitoring" differs from "worst case" sampling discussed in OHS Guideline G5.48-9 in that a larger number of samples are collected to account for day-to-day, as well as worker-to-worker, variability. The officer will not normally conduct the additional monitoring. The following is an acceptable process for carrying out the additional monitoring

  • collect samples over an appropriate period of time in order to obtain a reliable estimate of exposure,
  • group workers to be sampled on the basis of potential exposures (see the Note below),
  • take 6 - 10 samples from each group of workers,
  • calculate the mean exposure for each group
    • If the mean exposure for some workers in the group is much higher than for other workers, the group is not similarly exposed and should be split into two or more groups.
  • calculate the geometric standard deviation for each mean exposure
    • Formulae for calculating the standard deviation can be found in standard occupational hygiene references. Three references that are acceptable to the Board are listed in OHS Guideline G5.53-4.
  • calculate the 95% upper and lower confidence limits for each mean exposure
    • Formulae for calculating the upper and lower confidence limits can be found in standard occupational hygiene references. Three references that are acceptable to the Board are listed in OHS GuidelineG5.53-4.
  • apply the guidelines of compliance outlined in OHS Guideline G5.48-9.

Note:
Officers should consider whether the employer has grouped workers with similar patterns of exposure together. Such grouping would normally be based on an examination of work processes, procedures, job descriptions, process schedules and weather conditions. Groups of workers with similar patterns of exposure are referred to as "similarly exposed groups" or "homogeneous exposed groups".

G5.53-4 Occupational hygiene methods acceptable to the Board

Effective August 1, 1999

All elements of an assessment or monitoring program must be conducted using occupational hygiene methods acceptable to the Board. The Board accepts methods detailed in standard occupational hygiene references, such as

  • John R. Mulhausen and Joseph Damiano. A Strategy for Assessing and Managing Occupational Exposures. Published by the American Industrial Hygiene Association, Akron, Ohio, 1998, 2nd edition.
  • Neil C.Hawkins, Samuel K. Norwood, and James C. Rock. A Strategy for Occupational Exposure Assessment. Published by the American Industrial Hygiene Association. Akron, Ohio. 1991.
  • Nelson A. Leidel, Kenneth A. Busch, and Jeremiah R. Lynch. Occupational Exposure Sampling Strategy Manual. Published by the National Institute of Occupational Safety and Health. Cincinnati, Ohio. 1977.

    An exposure assessment/sampling guide is presently being considered by the Prevention Division for publication as a standard practice manual.

G5.54-1 Exposure Control Plan

Issued August 1999; Revised October 29, 2003; Editorial Revision January 2006; Editorial Revision February 1, 2008

Regulatory excerpt
Section 5.54(1) of the OHS Regulation ("Regulation") states:

An exposure control plan must be implemented when

    (a) exposure monitoring under section 5.53(3) indicates that a worker is or may be exposed to an air contaminant in excess of 50% of its exposure limit
    (b) measurement is not possible at 50% of the applicable exposure limit, or
    (c) otherwise required by this Regulation.

Purpose of guideline
The purpose of this guideline is to discuss when an exposure control plan is required. This includes providing specific sections under the Regulation where an exposure control plan is required.

When an exposure control plan is required
Section 5.54(1) of the Regulation requires the employer to implement an exposure control plan under certain specific circumstances. The elements that must be incorporated into the exposure control plan are listed in section 5.54(2).

An exposure control plan is required when any of the following conditions are present:

  • The results of exposure monitoring indicate that a worker is or may be exposed to an air contaminant at levels greater than 50% of its exposure limit.
  • Measurement is not possible at 50% of the applicable exposure limit.
  • An exposure control plan is required by another section of the Regulation.

If the employer has failed to conduct workplace monitoring under section 5.53(3), a WorkSafeBC prevention officer may order the employer to implement an exposure control plan if the prevention officer determines exposure exceeds 50% of the exposure limit.

The determination of whether an exposure control plan is required will typically be made on the basis of the additional monitoring under section 5.53(3). Worst-case sampling (see OHS Guideline G5.53-3) can also demonstrate exposure, although with less certainty. Where exposure greater than 50% of the exposure limit would occur only in an emergency, an emergency plan rather than an exposure control plan is required under sections 5.2 and 5.97 of the Regulation. For example, an accidental spill or leak of a substance may occur, which is otherwise contained or controlled below 50% of the exposure limit.

The word "may" in clause (a) in section 5.54(1) refers to situations where there is "possible exposure." The figure in OHS Guideline G5.48-9 shows that a guideline for determining possible exposure includes situations where the upper confidence limit is above the exposure limit and the lower confidence limit is below the exposure limit. For further clarification, refer to OHS Guidelines G5.48-9 and G5.53-3.

The levels of most common substances can be measured at the exposure limit. Even though exposure cannot be precisely measured or determined at 50% of the exposure limit, there may still be sufficient evidence for a knowledgeable person to reasonably conclude that t