Coal Tar and Coal-Tar Pitches
Results show that approximately 7,600 Canadians are exposed to coal tar and coal tar pitches in their workplaces; 93% of these workers are male. The largest exposed industrial groups are alumina and aluminum production and processing, foundation, structure, and building exterior contractors, highway, street and bridge construction, and foundries.
When exposure is examined by occupation, the largest exposed groups are roofers and shinglers (2,200 exposed), construction trades helpers and labourers (800 exposed), machine operators in mineral and metal processing (700 exposed), and heavy equipment operators (600 exposed).
Data Sources & Methods
Data used in developing the occupational estimates for coal tar and coal tar pitches were collected from several sources:
- The Canadian Workplace Exposure Database (CWED) contains over 500 measurements for coal tar and coal tar pitches exposure. These measurements were collected during the years 1981 to 2004 in Ontario and British Columbia workplaces.
- Canadian and US scientific peer reviewed publications that addressed coal tar and coal tar pitches exposure in Canada and the United States.
- Grey literature including technical reports from governments and international bodies.
Prevalence Estimate Method
CAREX defines exposure to coal tar and coal tar pitches as dermal exposure at work to levels significantly exceeding non-occupational background levels. Inhalation exposures to coal tar and coal tar pitch volatiles are not included in our exposure estimate as they overlap with exposures to polycyclic aromatic hydrocarbons (PAHs). Likewise, exposure to creosotes and naphthalene are not considered for this report. PAHs, creosotes and naphthalene are addressed under their specific CAREX occupational exposure estimates.
To determine the number of workers potentially exposed to coal tar and coal tar pitches 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 coal tar and coal tar pitches.
- Occupations and industries at risk of possible exposure to coal tar and coal tar pitches 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 coal tar and coal tar pitches.