Pesticide exposure and hepatocellular carcinoma risk: A case-control study using a geographic information system (GIS) to link SEER-Medicare and California pesticide data

•SEER-Medicare and Pesticide Use Report data were linked using ZIP Codes in a GIS.•This epidemiologic case-control study focused on California, United States.•Remote sensing land cover data identified populations at risk for pesticide exposure.•ZIP Code-level organochlorine pesticide exposure significantly elevated HCC risk.•ZIP Code organochlorines increased risk among males (no association among females).