Introduction Women constitute nearly half of the workforce. However, most of our knowledge about occupational diseases come from studies conducted on men.

Objective To describe occupational exposures experienced by women.

Methods Two case-control studies of postmenopausal breast cancer were conducted in Montreal in 1996 and in 2011. Questionnaires on lifetime occupational history were administered during in-person or telephone interviews. Experts reviewed subjects’ work history, assessing exposure to a list of 258 chemicals. Chemicals that were deemed to be present were categorized by concentration (‘low’, ‘medium’, ‘high’), where low represented a background occupational level and high was the highest level experienced in that work environment. We pooled exposure information from both studies by time period and by age of exposure.

Results In both studies combined, the three most prevalent exposures were cleaning agents, ozone, and organic solvents; the jobs in which these top 3 agents were present included nurses and waitresses (cleaning agents), secretaries and clerks (ozone), and housekeepers and elementary school teachers (organic solvents). For cleaning agents and ozone, most exposures occurred at a low concentration (>98%) while slightly higher exposures to organic solvents were found (14% medium and 2% high). The top 3 agents by time period were: <1950, fabric dust, aliphatic aldehydes, and cotton dust; 1950–1969, cleaning agents, aliphatic aldehydes, and organic solvents; 1970–1989, cleaning agents, ozone, and aliphatic alcohols; and ≥1990, ozone, cleaning agents and aliphatic alcohols. The prevalence of exposures differed for women exposed earlier versus later in their working life (predominant agents ≤35 years of age: cleaning agents, aliphatic aldehydes, aliphatic alcohols; >35 years of age were ozone, cleaning agents, organic solvents).

Conclusion Occupational exposures of women remain understudied; bringing out inconspicuous exposures can help better assess women’s occupational risks.