In the 1960s, tetrachlorethylene (TCE), also known as perchlorethylene, became the organic solvent of choice for dry cleaners1. About half of the TCE produced in the United States in 1990 was used for dry cleaning, and in the Nordic countries TCE use reached its peak around 1970 when it was the main solvent for dry cleaning1,2. The National Institute for Occupational Safety and Health (NIOSH) estimated that approximately 500,000 laundries may have been exposed to TCE3 in the early 1980s. From the early 1970s to the 1980s, the incidence of primary liver cancer increased in several countries4. Over the years, the association between TCE and liver cancer has been inconsistent between human epidemiological studies and associations found in animal experiments4. Motivated by inconsistencies in previous literature and experimental animal evidence, this article reviews published epidemiological studies presenting findings on tetrachlorethylene exposure and human liver cancer. Results: Two case-control studies 4,5, two nested case-control studies2,6 and two cohort studies1,7 reported estimates for the association between tetrachlorethylene (TCE) exposure and primary liver cancer. In one case-control study a nonsignificant association was found between occupational exposure to solvents and primary liver cancer, while the other observed a significant association. Hemberg et al. found that the odds ratio (OR) for heavy/moderate exposure versus little/no exposure was 2.3 (95% CI: 0.8, 7.0). The association was limited to women (Fisher's exact chi-square p = 0.007) with men having a nonsignificant odds ratio of 0.5. Stemhagen et al. found that among men, the OR for those who worked in laundry or dry cleaning compared to those who did not work in that profession was 2.50 (95% CI: 1.02,...... half of the paper.. ...tal Health Perspectives. 114(2):213-219.3. Asikainen U, Riala R. Primary liver cancer and solvent exposure. 147-153.5 cancer. A retrospective case-control study of primary liver cancer in New Jersey, American journal of epidemiology 1983;117(4):443-454.6. Lynge E, Carstensen B, Andersen O. Primary liver cancer and carcinoma to renal cells in laundry and laundry workers in Denmark, Scandinavian Journal of Work, Environment and Health, August 1995;21(4): 293-295.7. Ruder AM, Ward EM, Brown DP Mortality in dry cleaning workers: an update of the American Journal of Industrial Medicine February 2001;39(2):121-132.