Effects of Exposure to JP-8 in Humans

Knave et al. 1976 1978 1919 Overall average concentration, 300 mg/m3 (range, 85-974 mg/m3) Average employment duration of 17 yr 

Anger and Measurements taken in breathing High-exposure 

Storzbach zones of subjects median group had persistent 

21 of 30 workers reported recurrent acute symptoms on exposure exposed workers reported higher prevalence of neurasthenic symptoms, greater irregularity of performance on test of complex reaction time, greater performance decrement over time in simple reaction-time task, poorer performance in task of perceptual speed than control group 

Measurements taken in breathing zones of subjects median concentration of naphthalene, 1.9 pg/m3 (low-exposure group), 447 Pg/m3 (high-exposure group) median concentration of benzene, 3.1 pg/m3 (low-exposure group) and 242 pg/m3 (high-exposure group) 

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The effects of exposure to JP-8 on the human kidney were examined in a study recently completed by the U.S. Air Force. The preliminary results of that study are described below and summarized in Table 8-1. 

This chapter summarizes the findings on the cardiovascular system toxicity of jet-propulsion fuel 8 (JP-8) and related fuels presented in the National Research Council report Permissible Exposure Eevels for Selected Military Fuel Vapors (NRC 1996) and reviews additional studies on cardiovascular system toxicity of JP-8 and related fuels. Those studies are summarized in Table 10-1. The subcommittee used the available information to assess the potential toxic effects of exposure to JP-8 on the cardiovascular system in humans. 

No studies of humans or experimental animals have been done to assess reproductive performance after exposure to JP-8. There are human data that demonstrate that exposure to jet fuel (mostly JP-4) at below 6 ppm did not affect semen quality for aircraft maintenance personnel (Lemasters et al. 1999b). Ancillary studies in rats and mice (USAF 1978b Mattie et al. 1995) did not suggest an adverse effect on reproductive organs or reproductive performance. The testicular atrophy reported in mice exposed to JP-4 (Bruner et al. 1993) might have been secondary to the debilitating effect of chronic skin disease. 

Hepatic effects are the most sensitive end points for inhalation exposure to JP-5, JP-7, JP-8, and kerosene (ATSDR 1995c, 1995g, 1998b). The available intermediate and chronic MRLs for these fuels are based on hepatic effects in animals. Neurological effects, particularly central nervous depression, have been seen in humans exposed acutely to JP-5 vapors, but exposure-effect relationships have not been established. Male rat a2u-globulin nephropathy occurred with exposure to JP-5 and JP-7, but this effect is not considered relevant to humans. A 1-year exposure to JP-7 produced a small increase in the incidence of C-cell adenomas and kidney adenomas in male rats exposed to the vapor the kidney adenomas may have been related to male rat a2Ll-globulin nephropathy, an effect with questionable relevance to human health. 

The immunosuppressive effects of dermal JP-8 were dose-dependent 50 pL for 1-3 days was not significantly suppressive, nor were single doses smaller than 300 pL. The effects ofJP-8 were also time-dependent T-cell proliferation was suppressed within 3-4 days after a single exposure and lasted for about 3 wk. The human dermal dose equivalent to the threshold 300-pL dose in the mouse was calculated by the authors to be 100 mL. Those results raise concern about potential health effects of prolonged or repeated dermal exposure of military personnel to JP-8. 

Harris et al. reported that 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, exposure at 500 mg/m3 for 1 hr/day for 7 days led to decreased spleen weight and cellularity, and exposure at 1,000 mg/m3 for 1 hr/day for 7 days led to decreased ability of spleen cells to mediate several immune responses. Those studies raise concern about the potential of JP-8 to cause immunotoxicity. The subcommittee reviewed the methods used to generate the exposure atmospheres in the studies by Harris et al. and suspects that the total JP-8 concentration in the atmosphere may have been underreported. However, even if the actual concentration was 10 times as high as the lowest concentration at which effects were observed (100 mg/m3) (i.e., if exposure was at a concentration of 1,000 mg/m3), the observation of positive effects from a short exposure duration (1 hr/day for 7 days) at that concentration leads the subcommittee to conclude that the interim permissible exposure level of 350 mg/m3 might be too high to be protective of human health (assuming the application of commonly used uncertainty factors). 

Data to assess the potential of JP-8 to adversely affect reproduction and development are sparse. One study (Puhala et al. 1997) reported measurements of human exposures and the values for the components of jet fuels analyzed that were far below the TWA threshold limit values (see Tabel A-2). Data on the absorption of volatile hydrocarbon components of JP-8 suggest that systemic exposure is likely, by any route of exposure. The single published developmental toxicity study (Cooper and Mattie 1996) did not report an adverse effect on embryonic or fetal development in rats with oral treatment at up to 2,000 mg/kg/d on days 6-15 of pregnancy, except for a decrease in body weight of offspring. 

There are no human data on the effects of JP-8 on development. The animal data are sufficient to conclude that prenatal oral exposure at doses of 1,500 mg/kg/d and greater administered on gestation days 6-15 in rats causes developmental toxicity. These toxicity findings in rodents are assumed to be relevant for prediction of risk to humans. 

That subcommittee reported that data on potential adverse health effects of JP-8 on the kidney were sparse. No human studies had examined kidney toxicity of JP-8. An acute exposure to hydrocarbon-based solvents at high concentrations (doses not specified) has been reported in a case study to produce kidney failure (Beirne and Brennan 1972) the authors reported that a... 

No studies were found in the literature that examined potential female reproductive effects or developmental effects of JP-8 or other jet fuels in humans. One study assessed male reproductive effects of inhalation of jet fuel (type not specified) and hydrocarbon solvents after 15 and 30 wk of exposure. In that study, exposure to jet fuel increased sperm concentration in workers who fueled jets and decreased sperm linearity in flight-line workers exposure to jet fuels did not appear to affect semen quality in aircraft-maintenance workers. 

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