The US Agricultural Health Study enrolled 55,000+ farmworkers in order to examine the health implications of working in farming. One of the illnesses under the spotlight was prostate cancer, a growing problem in more industrially developed countries (MIDCs). In this study, whether there was a family history of prostate cancer or not, an increased risk of prostate cancer was linked to working with chlorinated pesticides and the pesticide methyl bromide.

Exposure to other chemicals also increased the risk, but only in families with a genetic susceptibility.