Results show that nearly 6,000 Canadians are exposed to acrylonitrile at work; 68% of these workers are male. The largest industrial groups exposed are plastic and rubber products manufacturing (where most acrylonitrile is used in Canada), in addition to motor vehicle parts manufacture, and the resin and synthetic fiber industry.
When exposure is examined by occupation, the largest exposed group is plastic processing machine operators (3,900 workers, or 2/3 of all exposed workers), followed by rubber processing machine operators (800 workers), and plastic products assemblers and finishers (350 workers). Other smaller groups of interest include material handlers and motor vehicle assemblers (acrylonitrile is used in motor vehicle parts manufacture to make foams and plastics).
Data Sources & Methods
Data used in developing the occupational estimates for acrylonitrile were collected from several sources:
- The Canadian Workplace Exposure Database (CWED) contains over 700 measurements for acrylonitrile exposure. These measurements were collected during the years 1984 to 1996 in Ontario workplaces.
- Canadian and US scientific peer reviewed publications that addressed acrylonitrile exposure in Canada and the United States.
- Grey literature including technical reports from governments and international bodies.
Prevalence Estimate Method
CAREX defines exposure to acrylonitrile as inhalation exposure at work to levels above those encountered in the general environment.
To determine the number of workers potentially exposed to acrylonitrile at work, CAREX occupational exposure experts used methods previously established in other peer-reviewed CAREX projects in Europe. A series of steps were taken to assign exposure proportions to occupations and industries at risk of exposure to acrylonitrile.
- Occupations and industries at risk of possible exposure to acrylonitrile were identified using any combination of data sources described above.
- The total number of workers in each identified occupation and industry intersection was obtained from Statistics Canada 2006 census data.
- A percentage of workers exposed was assigned to that occupation and industry intersection. Percentages were determined by consultation with existing evidence in the data sources, previously established methods from the Europe CAREX estimates and the expert judgement of CAREX occupational hygienists.
- The number of workers in the identified group is multiplied by the assigned percentage to calculate the prevalence estimate of workers exposed to acrylonitrile.