Workers typically exposed to RCF are involved in manufacturing, processing, or using products and equipment containing RCFs.[1] The largest occupational groups exposed to RCF include insulators, welders and related machine operators, labourers in mineral and metal processing, and machine operators in mineral and metal processing. Other potentially exposed workers are involved in installing high-temperature insulation materials, demolition work, and maintenance and repair.[2]

Removing RCF insulating material from industrial furnaces and walls has resulted in some of the highest concentrations measured in occupational settings.[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 refractory ceramic fibres (RCF) were collected from several sources:

1. The Canadian Workplace Exposure Database (CWED) contains approximately 200 measurements for RCF exposure. These measurements were collected during the years 1987 to 1994 in Ontario workplaces.
2. Canadian and US scientific peer reviewed publications that addressed RCF 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 RCF as inhalation exposure at work above levels that are generally encountered in the environment.

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

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