Most cytogenetic studies on painters reported increased levels of genetic damage, such as chromosomal aberrations, micronucleus formation, sister chromatid exchange, 23 and DNA single-strand breaks. Several studies showed a dose-response association with duration of work. Stratified analyses by tobacco-smoking status generally showed similar results in smokers and non-smokers. The Working Group concluded that there is “sufficient evidence in humans that occupational exposure as a painter causes cancers of the lung and urinary bladder”. Additionally, there is “limited evidence in humans”, mainly on the basis of studies of maternal exposure, that painting is associated with child hood leukaemia. Overall, occupational exposure as a painter is “carcinogenic to humans”(Group 1). 15

Firefighters are exposed to many toxic combustion products, including many known, probable or poss ible carcin ogens. These intermittent expo sures can be intense, and shortterm exposures can be high for resp ir able particulate matter and for some carcinogens, notably benzene, benzo [a] pyrene, 1, 3-butadiene, and formaldehyde.