Risk of leukemia as a result of community exposure to gasoline vapors: a follow-up study.

OBJECTIVES

To assess the temporal and spatial relationship of risk for total leukemia and AML (acute myelogenous leukemia) among community residents of an area in northeastern (NE) Pennsylvania (PA) affected by the Tranguch Gasoline Spill which occurred in the early 1990s.

METHODS

Standardized incidence ratios (SIR) were calculated for total leukemia and AML among 625 residents affected by the gasoline spill in relation to both PA and local county cancer incidence rates. The risk of total leukemia and AML among the gasoline exposed population was evaluated for the period prior to the spill, 1985-1989; during the time surrounding the spill, 1990-1994; and for a period subsequent to the spill, 1995-2001.

RESULTS

The incidence of total leukemia and AML was significantly elevated subsequent to the spill for the entire period 1990-2001 and was highest for the period 1995-2001, whether comparison was made to PA or local county leukemia rates. Based on comparison to PA rates, the SIRs for total leukemia and AML were 7.69 (95% CI=1.58-22.46) and 11.54 (95% CI=2.38-33.69) for the 1995-2001 period, respectively. Prior to the spill, 1985-1989, and during the period of the spill, 1990-1994, no cases of leukemia were identified among the affected residents.

CONCLUSIONS

These results suggest a possible association between chronic low level benzene exposure and increased risk of leukemia among residents of the Tranguch Spill Site in NE PA. Our study provides additional support to the growing body of evidence implicating low level benzene exposure and cancer risk. We recommend that other communities contaminated with gasoline vapor through leaking underground storage vessels be monitored for elevated risk of leukemia.