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Part 6 Substance Specific Requirements

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Toxic Process Gases

6.116 Definitions

In sections 6.117 to 6.132

"enclosure" means a room, cabinet or separation designed to contain equipment, machinery and vessels and to isolate accidental releases of toxic gas;

"toxic process gas" means a gas which

(a) meets the HPR Health Hazard Class — Acute Toxicity, Categories 1, 2 and 3 or the categories set out in the following table:

HPR Health Hazard Classes Hazard categories
Skin corrosion / irritation   1A 1B 1C 2    
Serious eye damage / irritation 1         2A 2B
Respiratory or skin sensitization   1A 1B        
Mutagenicity   1A 1B   2    
Carcinogenicity   1A 1B   2    
Reproductive toxicity   1A 1B   2    
Specific organ toxicity (repeated exposure) 1       2    


(b) is used for purposes of

(i) an industrial process in which a precursor is changed into a product,

(ii) refrigeration by means of a piped installation, or

(iii) treatment of materials, for example, in a disinfection system.

[Amended by B.C. Reg. 253/2001, effective January 28, 2002.]

[Amended by B.C. Reg. 30/2015, effective August 4, 2015.]

6.117 Application

Sections 6.118 to 6.132 apply to operations in which a toxic process gas is used, but do not apply to the handling or storage of flammable fuel gases or vapours, toxic waste emissions or the use of toxic process gases in manufactured articles.

6.118 Risk assessment

The employer must ensure that a risk assessment is conducted for toxic process gases.

6.119 Exposure control plan

If there is a risk of adverse health effect to workers from exposure to a toxic process gas, based on the risk assessment, the employer must develop and implement an exposure control plan meeting the requirements of section 5.54.

6.120 Procedures

(1) The employer must ensure that written work procedures providing instructions for the safe handling of the toxic process gas are prepared for all hazardous tasks in accordance with the risk assessment results, critical technical information and operations manuals.

(2) The employer must ensure that emergency procedures designed for the safe evacuation and rescue of all workers are established and tested on a regular basis.

(3) The procedures required by subsections (1) and (2) must be readily available to the workers at the workplace.

6.121 Education and training

The employer must ensure that

(a) workers are capable of operating the equipment and machinery in a safe manner by providing effective education and training, and

(b) records of education and training are maintained.

(c) Repealed. [B.C. Reg. 312/2003, effective October 29, 2003.]

[Amended by B.C. Reg. 312/2003, effective October 29, 2003.]

6.122 Enclosure

Where practicable, the employer must locate equipment and machinery such as tanks and compressors, handling toxic process gases in a separate enclosure that is

(a) designed, constructed and maintained to prevent fugitive emissions and accidental releases from entering occupied work areas,

(b) provided with exhaust ventilation to ensure an effective inward air flow into the enclosure at all times,

(c) provided with a safe means of entry and exit,

(d) designated as a restricted work area limited to entry by authorized personnel, and

(e) posted with signs which clearly identify the hazards and the precautions required for safe entry.

6.123 Testing

The employer must provide a safe means to check and test conditions inside an enclosure before entry by authorized workers.

6.124 Ventilation

The employer must

(a) ensure that ventilation systems are designed to exhaust toxic process gases directly to the outdoors in a safe manner,

(b) ensure that grilles providing makeup air from adjacent occupied areas are equipped with gas-rated, back-draft dampers,

(c) monitor critical parts of the ventilation systems, such as fan, motor and air flow, to ensure that workers are alerted to a malfunction of the system,

(d) ensure that ventilation ducting is vapour proof, dedicated and resistant to corrosion by the gas it carries, and

(e) where practicable, locate the fans on the outside of the building or structure to maintain the duct work within occupied work areas under a negative pressure differential.

6.125 Emergency ventilation

The employer must provide emergency ventilation that can be safely activated in emergency situations to ensure containment and control of an accidental release of a toxic process gas.

6.126 Shut-down device

(1) In the event of an emergency or accidental release, the employer must ensure that

(a) the gas supply can be shut down manually from a remote location or by the alarm system so as to isolate the reserve supply within the system and stop the generation or flow of the gas, or

(b) if the control measures required by paragraph (a) are not practicable, other effective measures, acceptable to the Board, are implemented to protect workers and other persons from exposure to the gas.

(2) When an automated or remote shut-down device is activated, the employer must ensure that operators are alerted to the emergency shut-down of the system.

[Enacted by B.C. Reg. 381/2004, effective January 1, 2005.]

6.127 Personal protective equipment

(1) The employer must provide appropriate personal protective equipment and ensure that workers wear it.

(2) A worker performing a hazardous work procedure on equipment or machinery where there is the risk of toxic process gas being released directly into the breathing zone, such as cylinder changing, system or line purging or draining, and leak detection and repair, must wear an appropriate respirator.

(3) A worker entering a restricted access enclosure must wear or carry an escape respirator.

[Amended by B.C. Reg. 312/2010, effective February 1, 2011.]

6.128 Monitors and alarms

(1) Where practicable, the employer must install continuous monitoring systems that detect fugitive emissions and accidental releases and effectively determine work conditions within the restricted access area.

(2) Continuous monitors must be connected to alarm systems to adequately warn workers of hazardous conditions and, when practicable, must be designed to safely activate appropriate control measures when emergency situations are detected.

(3) Monitoring and alarm systems must be

(a) tested at least monthly for proper operation, and

(b) calibrated at least annually

by authorized personnel using procedures set out in section 4.3 (2) or other procedures acceptable to the Board.

[Amended by B.C. Reg. 312/2003, effective October 29, 2003.]

[Amended by B.C. Reg. 188/2011, effective February 1, 2012.]

6.129 Pressure relief alarm systems

(1) The employer must ensure that all pressure relief valves or similar safety-release devices direct relief gases to the outdoors in a safe manner.

(2) The employer must ensure that an alarm or any other reporting system designed to inform the operators of a malfunction or emergency activates if a pressure relief safety device is engaged.

6.130 Identification of controls

The employer must ensure that

(a) all critical components of equipment and machinery handling toxic process gases are clearly identified, and

(b) the function of every control device can be readily determined.

6.131 Piping systems

(1) The employer must ensure that a piping system is

(a) constructed of compatible materials resistant to corrosion by the gas it carries,

(b) constructed to withstand the system pressures to which it will be subjected, and

(c) safely routed, supported and protected from impact damage, shock and vibration.

(2) The employer must ensure that piping and valve systems are leak and pressure tested, as required, before the system is put into operation.

(3) The employer must ensure that piping systems are equipped with isolation, pressure venting or bleed valves designed to purge the lines safely of residual gases before maintenance or servicing procedures.

6.132 Maintenance

The employer must ensure that the servicing and maintenance of equipment and machinery addresses all critical components.

[Amended by B.C. Reg. 312/2003, effective October 29, 2003.]

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