The General Motors/United Auto Workers (GM/UAW) cohort of 46,000 autoworkers is the largest study to date of workers exposed to metalworking fluids (MWFs). Follow-up has recently been extended through 1994, with a 50% increase in the number of deaths. An extensive exposure assessment has been conducted. Pancreatic cancer was previously investigated in this cohort and found it to be significantly associated with synthetic metalworking fluids used in grinding operations, OR = 3.0, 95% CI: 1.2-7.5. Synthetic fluids are of potential public health concern because their use is expanding. However, in the previous analysis, latency and cumulative exposures were limited because synthetics fluids did not come into widespread use until the early 1970's. Another ten years of follow-up has doubled the number of pancreatic cancer cases, as well as increased cumulative exposure to synthetic fluid in the cohort. Standardized mortality ratios (SMRs) for both pancreatic and hepatobiliary cancer have increased from the initial mortality study (1940-1984). The elevated risk for pancreatic cancer was also seen in blacks and females, the two most recently hired subgroups of workers. Separate nested case-control studies will be conducted for pancreatic and hepatobiliary cancer. Registries will be contacted to verify the cause of death for both cancers. Conditional logistic regression models will be fit to estimate exposure response relationships. Both cancers are considered in the same proposal for two reasons: the organs share a close anatomic and physiologic relationship, and the occupational health literature suggests similar risks in related industries.