1,3-Butadiene Occupational Exposures

1,3-Butadiene Occupational Exposures


Inhalation is the most important route of occupational exposure.[1] The potential for exposure exists in petroleum refining, as well as during production of purified butadiene monomer, various butadiene-based rubber and plastic polymers, and rubber and plastic products, such as tyres, hoses and a variety of molded objects.[2]


CAREX Canada estimates that approximately 4,000 Canadians are exposed to 1,3-butadiene in their workplaces. The largest industrial groups exposed are chemical, rubber, and plastic product manufacturing industries. The largest exposure groups by occupation are machine operators in the rubber and plastic processing industry.

Prevalence Estimate

Results show that approximately 4,000 Canadians are exposed to 1,3-butadiene in their workplaces; 83% of these workers are male. The largest industrial groups exposed are rubber products, basic chemical, and plastic product manufacturing.

When exposure is examined by occupation, the largest exposed groups include rubber processing machine operators (500 workers exposed) and plastic processing machine operators (400 workers exposed).

Workers exposed to 1,3-butadiene by industry

Workers exposed to 1,3-butadiene by region

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 1,3-butadiene were collected from several sources:

  1. The Canadian Workplace Exposure Database (CWED) contains over 300 measurements for 1,3-butadiene exposure. These measurements were collected during the years 1984 to 1996 in Ontario workplaces.
  2. Canadian and US scientific peer reviewed publications that addressed 1,2-dichloroethane 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 1,3-butadiene as inhalation and dermal contact at work above levels encountered in indoor or ambient air when there is no additional source of combustion (i.e. wood fire smoke or cigarette smoke).

To determine the number of workers potentially exposed to 1,3-butadiene 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 1,3-butadiene.

  1. Occupations and industries at risk of possible exposure to 1,3-butadiene 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 2006 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 1,3-butadiene.

1. National Toxicology Profile (NTP). 14th report on carcinogens for 1,3-butadiene (2016) (PDF)
2. International Agency for Research on Cancer (IARC). Monograph Vol. 100F 1,3-Butadiene (2012) (PDF)

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