Exposure to flour dust
at work can cause asthma
Bakery workers in B.C. are routinely exposed to allergens in flour dust, particularly when weighing, pouring, and operating dough mixers. Studies have shown that the concentration of airborne flour dust can be more than 200 times the occupational exposure limit for some operations.
What is flour?
Flour is a complex organic dust that can be made up of a
number of cereal types, including wheat, rye,
Why is flour dust a problem?
Flour contains naturally occurring chemicals that can induce allergy, respiratory sensitization and, at increasing exposures, occupational asthma (baker's asthma). One of the most potent allergens in flour is alpha-amylase.
Alpha-amylase is an enzyme that occurs naturally, in small amounts, in wheat flour. It is also added as a dough improver to break up large starch molecules and speed up the activity of the yeast.
Asthma has been reported in bakers since Roman times and is listed as one of the major causes of occupational asthma in Quebec and the United Kingdom (in the UK, a baker is considered to be in a "high risk" occupation). There may be a 30-year latency period between first exposure and the development of symptoms. Once sensitization occurs, even a small amount of the allergen can trigger an asthma attack.
In B.C., the eight-hour occupational exposure limit (OEL) for flour dust is 0.5 milligrams per cubic metre (mg/m3) of air. A recent study of 96 bakery workers in the Lower Mainland revealed airborne flour dust concentrations ranging between 0.1 mg/m3 to 110 mg/m3 (more than 200 times the OEL), depending on the work activity.
Typical dough mixer without cover
What can be done to reduce flour dust exposure?
Proper work practices can reduce worker exposure to flour dust.
Local exhaust ventilation control
Local exhaust ventilation is the most desirable means to reduce worker exposure to flour dust.
Dough mixer retrofitted with a cover and exhaust ventilation
Where to get more information
The Health and Safety Executive (HSE) of the UK has information on baker's asthma and recommendations for proper work procedures, respiratory protection, and engineering controls, which are posted on their web site: http://www.hse.gov.uk/asthma/bakers.htm.
WorkSafeBC Prevention Information Line: (604) 276-3100 or toll-free 1-888-621-SAFE (7233) or visit our web site at www.WorkSafeBC.com