Toxicity and occupational exposure assessment for Fischer-Tropsch synthetic paraffinic kerosene.

Fischer-Tropsch (FT) Synthetic Paraffinic Kerosene (SPK) jet fuel is a synthetic organic mixture intended to augment petroleum-derived JP-8 jet fuel use by the U.S. armed forces. The FT SPK testing program goal was to develop a comparative toxicity database with petroleum-derived jet fuels that may be used to calculate an occupational exposure limit (OEL). Toxicity investigations included the dermal irritation test (FT vs. JP-8 vs. 50:50 blend), 2 in vitro genotoxicity tests, acute inhalation study, short-term (2-week) inhalation range finder study with measurement of bone marrow micronuclei, 90-day inhalation toxicity, and sensory irritation assay. Dermal irritation was slight to moderate. All genotoxicity studies were negative. An acute inhalation study with F344 rats exposed at 2000mg/m(3) for 4hr resulted in no abnormal clinical observations. Based on a 2-week range-finder, F344 rats were exposed for 6hr per day, 5 days per week, for 90days to an aerosol-vapor mixture of FT SPK jet fuel (0, 200, 700 or 2000mg/m(3)). Effects on the nasal cavities were minimal (700mg/m(3)) to mild (2000mg/m(3)); only high exposure produced multifocal inflammatory cell infiltration in rat lungs (both genders). The RD50 (50% respiratory rate depression) value for the sensory irritation assay, calculated to be 10,939mg/m(3,) indicated the FT SPK fuel is less irritating than JP-8. Based upon the proposed use as a 50:50 blend with JP-8, a FT SPK jet fuel OEL is recommended at 200mg/m(3) vapor and 5mg/m(3) aerosol, in concurrence with the current JP-8 OEL.