Acrylonitrile Occupational Exposures

Acrylonitrile Occupational Exposures

Overview

Inhalation and dermal contact are the most important routes of occupational exposure.[1] CAREX Canada estimates that 4,100 Canadians are exposed to acrylonitrile in the workplace.

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The largest industrial groups exposed are plastic product manufacturing, followed by rubber product and motor vehicle parts manufacturing. Occupations that are most exposed to acrylonitrile include plastic processing machine operators, rubber processing machine operators, and plastic products assemblers, finishers, and inspectors.

A risk assessment by the EU summarized European occupational exposure data and identified the highest mean exposures in fibre production, although they were still ≤ 1 ppm.[2] Further exposures can occur during industrial processes such as burning synthetic polymers, working with glues and adhesives, and firefighting.[3] Firefighters may be exposed to acrylonitrile because the chemical can be released from burning plastics.[3] However, acrylonitrile is very flammable itself and is likely to burn off in a fire, producing hydrogen cyanide, another very toxic gas.[1]

Prevalence Estimate

Results show that nearly 4,100 Canadians are exposed to acrylonitrile at work; 72% 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 (where acrylonitrile is used to make foams and plastics), and the resin and synthetic fibre industry.

When exposure is examined by occupation, the largest exposed group is plastic processing machine operators (2,700 workers, or 2/3 of all exposed workers), followed by rubber processing machine operators (590 workers), and plastic products assemblers and finishers (290 workers).

The number of workers exposed to acrylonitrile decreased by approximately 1,800 workers from 2006 to 2016 (a 31% decrease). This was primarily driven by a decrease in the number of workers in the plastics and rubber manufacturing industries.

Workers exposed to acrylonitrile by industry in 2016

Workers exposed to acrylonitrile by region in 2016

Click the second tab to view total number of workers exposed.

* = < 50 workers
Methods and Data

Our Occupational Approach page outlines the general approach used to calculate prevalence and exposure level estimates for workplace exposures.

Data Sources

Data used in developing the occupational estimates for acrylonitrile were collected from several sources:

  1. 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.
  2. Canadian and US scientific peer reviewed publications that addressed acrylonitrile exposure in Canada and the United States.
  3. 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.

  1. Occupations and industries at risk of possible exposure to acrylonitrile were identified using any combination of data sources described above.
  2. The total number of workers in each identified occupation and industry intersection was obtained from Statistics Canada 2016 census data.
  3. 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.
  4. The number of workers in the identified group is multiplied by the assigned percentage to calculate the prevalence estimate of workers exposed to acrylonitrile.
Sources

1. World Health Organization (WHO). CICAD on Acrylonitrile (2002) (PDF)
2. European Union. Risk Assessment Report: Acrylonitrile (2004) (PDF)

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