A general job-exposure matrix for the purpose of historical exposure assessment of petroleum refinery workers was constructed using the published literature, industry reports, government documents, engineering texts, worker recommendations, and historical process and industrial hygiene information from three refineries in the Beaumont-Port Arthur area of Texas. The matrix was then modified for one of these refineries to make links between jobs and exposures more company-specific. The company-specific matrix will be used in a related case-control mortality study of active and retired members of two Texas locals of the Oil, Chemical, and Atomic Workers International Union. The historical exposure assessment capabilities offered by this matrix will allow the case-control study, which builds on work by Terry Thomas and colleagues in 1982 and 1984, to investigate links between chemical exposure agents and specific cancers. The general job-exposure matrix can be used in future epidemiology studies of petroleum refinery workers whose job histories are accessible to the researcher. If resources are available, the matrix should be modified to more accurately represent the exposure profile at the specific refineries of interest. The matrix can also be used in its present state to provide a "sketch" of the exposure histories of petroleum refinery workers, but its power will be limited by a lack of specificity.