Here’s a small study (1704 workers) of people exposed to "perc" (perchloroethylene a/k/a tetrachloroethylene): "Mortality and End-Stage Renal Disease Incidence Among Dry Cleaning Workers". Small increases in the overall risk of dying from cancer of any kind and from esophageal, lung and tongue cancers in particular were identified. Most significant was a near doubling of the risk of developing end-stage renal disease. As risk appeared to rise with increasing duration of employment (a proxy for exposure) at least for some of the cancers it was concluded that perc, rather than lifestyle or socioeconomic factors, was responsible and that it’s therefore likely a human carcinogen.
Yet just last October a study of 10,389 Swedish dry-cleaning and laundry workers (the largest yet of perc-exposed workers) found no increase in cancer risk either overall or for those sorts of cancers thought possibly related to perc exposure. The article, which is free, has a great discussion of the perc controversy, the various positions taken by IARC, the NTP, the ACGIH and others, and a brief discussion about why the healthy worker effect might not be an issue in occupational cancer inquiries. It was published in the International Archives of Occupational and Environmental Health as "Cancer Morbidity in Swedish Dry-Cleaners and Laundry Workers History: Historically Prospective Cohort Study".