Cancer, Cardiovascular Disease, and Non-Malignant Respiratory Disease in Sudbury Nickel Refinery and Electrowinning Workers


This study will update a subset of the Vale Ontario nickel workers cohort; specifically, refinery and electrowinning workers employed in the Copper Cliff Nickel Refinery (CCNR). The goals of the study are to update the cohort to include workers employed up to 2019, extend follow up for cancer incidence to 2019, and add cardiovascular disease and non-malignant respiratory disease incidence for 1991-2019. This updated cohort will be used to assess the risk of cancer, cardiovascular disease, and respiratory disease among these workers.

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Exposure to nickel compounds can cause respiratory cancers including lung cancer. It may also cause cardiovascular effects, chronic respiratory disease, and allergic contact dermatitis. Other potentially hazardous exposures that have been measured at the facility include lead, arsenic, and cobalt.

The original Vale Ontario nickel workers cohort was constructed from payroll records going back to 1900 for workers with at least six months employment, still working or alive by January 1950. This cohort has been updated five times by adding new hires and extending follow up for mortality and cancer incidence. Higher risks of respiratory cancer have been confirmed for refinery and smelter workers in particular, with the last follow-up ending in December 2000 (Seilkop et al, 2016Lightfoot et al, 2016).

Recently, concerns have been raised by the Vale Joint Occupational Health Committee about potential cancer and cardiovascular disease risks among the nickel refinery and electrowinning workers at Vale’s Copper Cliff Nickel Refinery, which began operations in 1973. This group of workers is a subset of the Vale Ontario nickel workers cohort but has not been studied separately.


A Vale nickel refinery cohort will be created using data from the original Vale cohort and updated to include male and female employees who have completed at least six months of work in the nickel refining or electrowinning areas of Vale’s Copper Cliff Nickel Refinery between 1973 and 2019.

The new cohort will be linked to provincial administrative health databases to identify cancer, cardiovascular disease and respiratory disease incidence up to 2019. Incidence rates will be compared to the general Ontario population, and possibly to the population of Northeastern Ontario. Analyses will also be undertaken to explore the risk of disease by work area, duration of employment, and other factors. As part of this study, the research team will assemble all available data on exposure to nickel and other toxic air contaminants at the Copper Cliff Nickel Refinery. This data will be used to assign exposure levels to groups based on department and/or occupation at the facility.


This study will evaluate the risks of developing cancer, cardiovascular disease and respiratory disease among workers exposed to nickel and other compounds at Vale’s Nickel Refinery Complex in Copper Cliff, Ontario. This study has the potential of directing the industry to safer processes for refining nickel, thereby protecting the health of current and future nickel workers.

Progress (updated March 2021)

The updated 2000 to 2019 data is being compiled and will be verified and joined with the existing 1973 to 2000 employment data prior to record linkage and data analysis.


This study was initiated at the request of the Vale Ontario Operations Joint (Vale/United Steel Workers) Occupational Health Committee. Funding for this study was provided by Vale.

Research Team
Paul Demers
Nancy Lightfoot
Laurentian University
Colin Berriault
Jonathan Fan
Institute for Work & Health