various fuels and a compendium of exposure limits recommended by national and international government bodies and other organizations. That information is followed by a description of the toxicokinetics of the fuels and a summary of experimental studies conducted in humans and animals, focusing on studies that yielded information on chronic adverse health effects, on genetic susceptibility, or on interactions between fuels and other substances.
The fuels discussed here have been the subjects of comprehensive reviews by the Agency for Toxic Substances and Disease Registry (ATSDR 1995a, 1995b, 1995c, 1998, 1999b), the International Agency for Research on Cancer (IARC 1989), the National Research Council (NRC 1996b, 2003), and Ritchie et al. (2003). The reader is referred to those sources for more detailed reviews of the toxicologic data on those fuels.
Several components of hydrocarbon fuels—benzene, toluene, xylenes, and naphtha—were reviewed in Gulf War and Health, Volume 2: Insecticides and Solvents (IOM 2003) and will not be addressed individually here. The Committee on Gulf War and Health: Literature Review of Insecticides and Solvents found sufficient evidence of a causal relationship between benzene and both acute leukemia and aplastic anemia. The reader is referred to that volume for more information on adverse health effects associated with exposures to benzene, toluene, xylenes, and naphtha.
Some of the physical and chemical properties of gasoline, kerosene, diesel, JP-4, JP-5, and JP-8 are presented in Table 3.1. They are arranged in order of increasing carbon number, that is, according to composition of relatively longer hydrocarbon chains or heavier cut of distillates. Naphthas, middle distillates used in mixing gasoline and composed primarily of C5-C13 aliphatic hydrocarbons, would fall between gasoline and JP-4. Kerosene, JP-5, and JP-8 are very similar in composition, differing primarily in the additive packages that characterize them; hence they share several synonyms.
Limits of occupational exposures to several fuels have been recommended by such organizations as the American Conference of Governmental Industrial Hygienists (ACGIH), ATSDR, IARC, the National Institute for Occupational Safety and Health (NIOSH), and the Occupational Safety and Health Administration (OSHA). Those values, as summarized in Table 3.2, give a sense of what fuel exposures are currently considered safe.