lion gallons of JP-8 per year for powering aircraft and land-based military vehicles. Quantitatively and qualitatively, JP-8 is probably responsible for the most common and abundant potential chemical exposure of DOD and NATO personnel. Occupational exposure of military and civilian personnel to JP-8 may occur in the following settings (see Table 2-1): transportation and storage of JP-8 fuel; aircraft fueling and defueling; maintenance of aircrafts; cold engine starts and performance testing; and operation and maintenance of other Air Force equipment and machinery. Air Force personnel working in aircraft fuel-cell maintenance shops and fuels-specialty and fuels-transportation shops are probably at the greatest risk for exposure to JP-8 (ATSDR 1998; R. Gibson, U.S. Air Force, personal communication, 2001). Additional exposure scenarios include application of JP-8 in fueling military tent heaters, use of fuel as an aircraft heat sink, and cleaning and degreasing with fuel (CDC 1999; Zhou and Cheng 2000; Cheng et al. 2001). During the Persian Gulf War, JP-8 was routinely used to control and suppress desert sand, and combusted JP-8 fuel was used to obscure troops and equipment (CDC 1999). With desert surface temperatures commonly exceeding 120ºF, substantial exposure may have occurred as a result of vaporization of JP-8. When vaporized jet fuel mixes with wind-blown ultrafine desert sand particles, pulmonary exposure is highly possible.
Deliberations on the scientific basis of the interim permissible exposure level (PEL) of 350 mg/m3 for JP-8 required the subcommittee to review relevant exposure assessment, epidemiologic, and toxicologic data. The studies all involved exposure to JP-8 or similar compounds; however, in many studies it is a challenge to qualitatively and quantitatively assess the exposure and dose of components of JP-8. Measurement of occupational exposures in various settings is problematic because JP-8 is a complex mixture of chemicals and personnel may be exposed to vapors, aerosols, or both, depending on the workplace setting. Furthermore, there are no standardized industrial hygiene sampling methods or analytical methods for JP-8. Ambient concentrations have been measured with standard industrial-hygiene methods to quantify some components of JP-8 (mostly aromatic substances, including benzene, naphthalene, toluene, and xylene). Given that the major chemical constituents of JP-8 are C9-C17+ aliphatic hydrocarbons, it is unclear how these aromatic components represent a true measure of total occupational exposure to JP-8.