A large cohort of petroleum refinery workers with long duration of employment, long latency, and relatively young age at hire had its vital status updated through Dec. 31, 1980. The standardized mortality ratio (SMR) for all causes was 78. Each nonneoplastic cause had an SMR below 100, including SMRs of 63 for emphysema and for all diseases of the genitourinary system and of 73 for chronic nephritis. The SMR for all cancers was 87. SMRs for specific neoplasms included digestive system, 90; lung, 85; kidney, 68; brain, 89; leukemia, 101; multiple myeloma, 123; unspecified lymphoma, 112; polycythemia vera (four deaths), 455; myelofibrosis (three deaths), 201; and benign and unspecified brain neoplasms, 108. There were nine deaths from mesothelioma; all nine employees had more than 20 years of employment, with an SMR of 241.