Polychlorinated Biphenyls Occupational Exposures

Polychlorinated Biphenyls Occupational Exposures

Overview

Inhalation, dermal absorption and ingestion are all potential routes of occupational exposure to PCBs.[1]

CAREX Canada estimates that approximately 8,100 Canadians are exposed to polychlorinated biphenyls in their workplaces. The largest industrial groups exposed are specialty trade contractors (e.g. electricians) in construction and electric power generation, transmission, and distribution industries. Other important industries exposed to PCBs are transportation equipment manufacturing, mining, and oil and gas extraction.

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The largest occupational groups exposed to PCBs include industrial electricians, electrical power line and cable workers, contractors and supervisors in electrical and telecommunication trades, electrical mechanics, and electricians. Other occupational exposures may occur in workers involved in waste storage and incineration, and contaminated site remediation.[2,3] Welders and general maintenance workers in various industries may also encounter PCBs in old industrial paints and coatings.[2] Exposure may also occur during accidental spills or fires involving equipment containing PCBs.[1,4]

Prevalence Estimate

Results show that more than 8,000 Canadian workers are potentially exposed to polychlorinated biphenyls (PCBs) at work; 97% of these workers are male. Industries with the largest numbers of exposed workers include specialty trade contractors (where most of the electricians are captured) and electric power generation, transmission and distribution. Other industries with notable worker exposure to PCBs are transportation equipment manufacturing and mining and oil and gas extraction (many industrial electricians are captured in both industries).

When exposure is examined by occupation, important occupational groups with the largest number of exposed workers include industrial electricians (3,000 exposed), electrical power line and cable workers (1,200 exposed), contractors and supervisors in electrical and telecommunication trades (1,100 exposed), electrical mechanics (800 exposed), and electricians (700 exposed).

Workers exposed to PCBs by industry

Workers exposed to PCBs 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 polychlorinated biphenyls (PCBs) were collected from several sources:

  1. The Canadian Workplace Exposure Database (CWED) contains approximately 200 measurements for PCBs exposure. These measurements were collected during the years 1981 to 2004 in Ontario and British Columbia workplaces.
  2. Canadian and US scientific peer reviewed publications that addressed PCBs 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 PCBs as inhalation exposure at work to levels likely to exceed non-occupational exposure via indoor or outdoor air.

To determine the number of workers potentially exposed to PCBs 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 PCBs.

  1. Occupations and industries at risk of possible exposure to PCBs 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 PCBs.
Sources

1. National Toxicology Program (NTP). 14th Report on Carcinogens for Polychlorinated Biphenyls (2016) (PDF)
2. Agency for Toxic Substances and Disease Registry (ATSDR). Toxicological Profile for Polychlorinated biphenyls (PCBs) (2000) (PDF)
3. Health Canada. It’s Your Health: PCBs (2011) (PDF)
4. Agency for Toxic Substances and Disease Registry (ATSDR). ToxFAQs Fact Sheet – Polychlorinated biphenyls (2001) (PDF)

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