The largest industrial groups exposed include public administration (e.g. police officers), followed by building equipment contractors, and automotive repair and maintenance. In terms of occupation, the two largest exposed groups are welders, followed by police officers. Other large occupational groups that are at higher risk to lead exposure include auto mechanics, plumbers, and steamfiiters, pipefitters, and sprinkler system installers.

Additional occupations that are exposed include workers involved in mining, lead smelting and refining industries, battery production or recycling, steel welding or cutting operations, construction, rubber products and plastics industries, printing industries, and firing ranges.[2]

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 lead were collected from several sources:

1. The Canadian Workplace Exposure Database (CWED) contains over 10,500 measurements for lead 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 lead 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 lead as inhalation exposure at work above average levels expected in the general environment (including food sources).

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

1. Occupations and industries at risk of possible exposure to lead 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 lead.

Exposure Level Method

CAREX uses available workplace exposure measurements in the CWED to create exposure level categories by industry and occupation. For lead and inorganic lead compounds, these categories are:

Category 1: Low Exposure

A group of workers (people in the same job category and industry) is put in this exposure category for one of two reasons:

1. The are no valid measurements, but a hygienist identified this group as typically exposed during literature and other reviews;
2. There are valid exposure measurements in the CWED and a hygienist review determined that exposure is plausible; AND EITHER:

1. 1. There are less than 10 samples available in the CWED, OR
   2. There are ≥10 measurements available but they do not meet the criteria for Moderate Exposure.

Category 2: Moderate Exposure

A group of workers is put in this exposure category if:

1. There are at least 25 individual samples in the CWED, AND
2. 20% or more samples have a value higher than 0.025 mg/m³ (which is half the current occupational exposure limit for lead).

OR

1. There are at least 10, but less than 25, individual samples in the CWED, AND
2. 20% or more samples have a value higher than 0.05 mg/m³ (which is the current occupational exposure limit for lead).

Category 3: High Exposure

A group of workers is put in this exposure category if:

1. There are at least 25 individual samples in the CWED, AND
2. 20% or more samples have a value higher than 0.05 mg/m³ (which is the current occupational exposure limit for lead).