The Tranguch Gasoline Spill leaked 50,000-900,000 gallons of gasoline from underground storage tanks, potentially exposing an area of Hazle Township and Hazleton, Pennsylvania, to chronic low levels of benzene since at least 1990. A retrospective cohort study of 663 individuals representing 275 households assessed whether affected residents were at increased risk for cancer from 1990-2000 compared with the Pennsylvania populace. Age-adjusted standard incidence ratios (SIRs) were calculated using Pennsylvania rates to determine expected numbers. The age-adjusted SIR for the gasoline-affected area was 4.40 (95% confidence interval: 1.09-10.24) for leukemia. These results suggest an association between living within the area affected by the Tranguch Gasoline Spill and increased risk for leukemia.