Effects of short-term high-dose and low-dose dermal exposure to Jet A, JP-8 and JP-8 + 100 jet fuels

Occupational and environmental exposures to jet fuel recently have become a source of public and regulatory concern. This study investigates the cutaneous toxicity of three fuels used in both civilian and military aircraft. Pigs, an accepted animal model for human skin, were exposed to low-dose (25 microl or 7.96 microl cm(-2)) or high-dose (335 microl or 67 microl cm(-2)) Jet A, JP-8 and JP-8 + 100 under occluded (Hill Top) chamber or cotton fabric) and non-occluded conditions for 5 h, 24 h and 5 days. To mimic occupational exposure, fuel-soaked fabric (high dose) was used. Erythema, edema, transepidermal water loss (TEWL) and epidermal thickness were quantified. High-dose fabric occluded sites had slight erythema at 5 h with increased erythema at 5 days. No erythema was noted in any of the occluded (Hill Top) or non-occluded sites at any of the time points. Morphological assessments depicted slight intracellular epidermal edema at all time points. An increase in change in TEWL (DeltaTEWL) was observed at the 5-h and 24-h fabric and Hill Top occluded treatments and a decrease at the 5-day fabric and Hill Top occluded sites. In all 5-day JP-8 + 100 fabric sites, intracorneal microabscesses filled with inflammatory cells were observed. Epidermal thickening was significant (P < 0.05) in all three jet fuels at the high-dose fabric sites, with JP-8 + 100 being the thickest. The epidermal rete peg depth increased significantly (P < 0.05) at 24 h and 5 days with Jet A, JP-8, and JP-8 + 100 in the fabric sites. No significant differences were noted in the 5-day non-occluded fabric and Hill Top occluded and non-occluded sites. Jet fuel JP-8 + 100 tended to have the greatest proliferative response. In conclusion, the high-dose fabric-soaked exposure at 5 days to Jet A, JP-8 and JP-8 + 100 fuels caused the greatest increase in cutaneous erythema, edema, epidermal thickness and rete peg depth compared with high-dose non-occluded or low-dose exposure under Hill Top occluded and non-occluded conditions.