This paper explores the rise of arsenic-containing pesticides during the first half of the twentieth century and their potential role in explaining rising cancer mortality during the following decades in the United States. I first examine the long-term health effects of arsenical pesticide exposure on Pennsylvania farmers by linking men between historical state farm census and death certificates. I find men that were more likely to be exposed to arsenic based on their individual crop choices were more likely to die from cancer types attributed to arsenic. Additionally, living in townships where more pesticides were used is also associated with likelihood of death by cancer among farmers and shorter life expectancy among their sons. Expanding this analysis to other states by combining national industry surveys and mortality data yield similar results. Health effects are strongest among younger cohorts who spent more time in the pesticide era.