cause occupational exposures to JP-8 vapors and aerosols are known to occur, the Air Force requested that the National Research Council (NRC) again review the available toxicologic, epidemiologic, exposure, and other relevant data on JP-8; independently reevaluate the scientific basis of the PEL of 350 mg/m³ for JP-8; identify data gaps; and make recommendations for future research relevant to deriving the PEL. The NRC assigned this project to the COT Subcommittee on Jet-Propulsion Fuel 8, which prepared this report.

To address its charge, the subcommittee reviewed data on physical and chemical properties of JP-8, toxicokinetics of JP-8, epidemiologic and toxicologic evidence of adverse health effects of JP-8, and Air Force operational scenarios that might result in exposure to JP-8 vapors and aerosols. In addition to reviewing health-effects data on JP-8, the subcommittee reviewed toxicity data on kerosene and other kerosene-based fuels (such as JP-5) that are similar to JP-8. The subcommittee reviewed toxicity data on JP-8 vapors as well as JP-8 aerosols. The subcommittee used the available data to evaluate the scientific basis of the Air Force interim PEL of 350 mg/m³.

The health-effects data on JP-8 and related fuels were reviewed for the following end points: respiratory tract toxicity, neurotoxicity, immunotoxicity, liver toxicity, kidney toxicity, reproductive and developmental toxicity, cardiovascular toxicity, genotoxicity, and carcinogenicity. JP-8 was found to be potentially toxic to the immune system, respiratory tract, and nervous system at exposure concentrations near the interim PEL of 350 mg/m³. Those toxicities are summarized below.

No immunotoxic effects were found in a study in which F344 rats and C57BL/6 mice were exposed to JP-8 vapors at concentrations up to 1,000 mg/m³ on a continuous basis for 90 days. However, in other studies, inhalation exposure of C57BL/6 mice to JP-8 aerosols at a concentration of 100 mg/m³ for 1 hr/day for 7 days led to decreased cellularity of the thymus;