Historical exposure assessment was conducted for a community-based case-control study of renal cell disease and total hydrocarbon exposure. Based on occupational histories of 658 subjects, each job held by each subject was coded with the standard industrial classification (SIC) and the standard occupational classification (SOC), and entered into a Paradox (relational database) file, resulting in 3159 SIC/SOC/decade combinations. Expert industrial hygienists were asked to provide exposure estimates for occupations in industries for which they professed at least moderate expertise; between two and five experts were identified for each two-digit SIC code. Because it was not possible to obtain expert panel estimates for all of the SIC/SOC combinations reported by subjects, the assessments were supplemented when possible with values obtained from the literature and from the Occupational Safety and Health Administration's computerized information system (OCIS). Data from the expert panel, the literature, and the OCIS database were individually evaluated to develop an estimated exposure for each SIC/SOC/decade combination, which was stored in a second Paradox file. This file was cross-matched with the subject data file to calculate an estimated lifetime occupational hydrocarbon exposure in ppm-years for each subject. Recommendations include use of interviewers trained in industrial hygiene, solicitation of exact employment dates from subjects, use of coders familiar with the area from which the study subjects are drawn, and careful evaluation of the occupational coding scheme. Finally, OCIS would be much more useful if it included coding for job titles.