Canadian Occupational Safety

14 Canadian Occupational Safety www.cos-mag.com fl our is the number 1 cause of occupational asthma in France. While the occupational exposure limit (OEL) for fl our dust particulates varies across the country, many provinces follow the guidelines from the American Conference of Industrial Hygienists, which imparts a threshold limit value of 0.5 milligrams per cubic metre of air (mg/m3) for inhalable fl our dust. But when it comes to actual expo- sures, bakery workers are exposed to signifi cantly more dust than the limits. A study of 96 bakery workers in Brit- ish Columbia revealed airborne fl our dust concentrations ranging between 0.1 mg/m3 to 110 mg/m3 (more than 200 times the OEL), depending on the work activity. Workers in industrial or traditional bakeries could be exposed to up to 7.8 mg/m3 and mill workers up to 16 mg/m3. RECIPE FOR PREVENTION Preventing baker's asthma can be tricky since fl our is prevalent in almost every part of a bakery. Flour and other dusts pose an inhalation hazard when weighing and adding ingredients, mixing ingredients with fl our, fl ouring the work surface, pro- cessing the dough through turning, fl ouring and dividing and also when cleaning the equipment. While the fi rst step in the hierarchy of controls for preventing baker's asthma O ne Saturday in October 2007, Shirley Labelle was working overtime in a very large bakery plant in south- ern Ontario when she couldn't get suffi cient oxygen into her lungs. "It took up too much oxygen to even move; even to raise my arm, it was too much. I was just basically standing there and it was getting worse," she says. "I was petrifi ed. I said 'I'm healthy what's going on?'" Things didn't get much better over the weekend, so fi rst thing Monday morning she went to see her doctor and her breathing test showed obvious impairment. Her doctor originally diagnosed her with emphysema, but Labelle wanted to get a second opinion. After about three months of testing with various specialists, she was diagnosed with baker's asthma, an occupational respiratory disease that can occur in bakery workers. The signs and symptoms of baker's asthma are the same as those who suffer regular asthma: coughing, shortness of breath, tightness in the chest and wheezing. After 17 years of working in the bakery, Labelle's fi rst sign of the disease was a non- productive cough. is elimination, this is virtually impossible in a bakery that needs certain specifi c items to make its fi nal product. The next step is to try and substitute the asthma-producing products but this can be a challenge in a bakery as well. "It's really hard for a baker to change the fl our because the recipe is usually their own; it's always a special recipe and according to a certain kind of bread or certain kind of pastry, you really have to use a certain kind of fl our," says Simon Aubin, an industrial hygienist at the Institut de recherche Robert-Sauvé en santé et en Sécurité du travail (IRSST) in Montreal. If possible, some substitution options include liquid enzymes, granulated (instead of powered) improvers and organic fl our. "The more the fl our dust is small in terms of particle size, the more it's going to be easier to get suspended in the air," says Aubin. "If you use more organic fl our, which hasn't been processed too much in the mill, the particle size will be bigger and it would be a bit less of a problem." Controlling the level of fl our dust can be achieved by enclosing dusty machinery. For example, a tight lid should be put on the mixer at the very beginning when the fl our is dry. "It came on like a sneeze, it was that fast. Because it was non-productive, you continually have that itch there to cough all the time," she says. "That was continuous for months." Breathing in fl our dust and other substances common in traditional bakeries, larger commercial plants or fl our mills causes baker's asthma. Examples include: • fl our and grains (wheat, rye, barley, soy and buckwheat) • additives, improvers, emulsifi ers, enzymes (alpha amylase) • other allergens (yeast, eggs or egg powder, sesame seeds and nuts). Baker's asthma is a common occupational disease in Canada and around the world. According to Michael Pysklywec, a physician at the Occupational Health Clinics for Ontario Workers in Hamilton, the prevalence is "strikingly high" with anywhere between fi ve per cent and 25 per cent of people in the industry developing the disease. In Quebec, flour/cereal dust is one of the top three causes of occupational asthma. In the United Kingdom, a baker is considered to be in a "high risk" occupation. A new study presented at the European Respiratory Society International Congress in September revealed Proper ventilation, local exhaust, good work practices needed to prevent baker's asthma POWER POWER By Amanda Silliker

• Cover