A One-Year Inhalation Toxicity Study of Otto Fuel 2

Abstract : A 1-year industrial type (6 hours/day, 5 day/week) inhalation exposure was conducted to evaluate the oncogenic potential of the torpedo fuel, Otto Fuel II. Exposure levels of 1.4 mg/cu m and 240 mg/cu m were based on analyzed 1-2 propylene glycol dinitrate (PGDN) concentrations, the major component. Dogs (male and female beagle), rats (male and female Fischer 344), and mice (male and female C57BL/6) were exposed to the lower concentration, while only rats and mice were exposed to the higher concentration. Dogs appeared to be the most sensitive species tested with measurable reductions in RBC, hematocrit, and hemoglobin levels. Mildly increased methemoglobin was also observed in dogs exposed to 1.4 mg/cu m and rats exposed to 240 mg/cu m. No other significant effects were noted in rats exposed at either concentration. Microscopic examination of tissues collected from dogs, rats, and mice exposed to Otto Fuel II failed to suggest any significant exposure related non- neoplastic changes. Similarly, exposure to Otto Fuel II also failed to increase the incidence of neoplastic changes. Rare primary bone tumors were noted in four rats exposed to PGDN. However, the incidence of these tumors in exposed rats was not increased in a dose related fashion despite the extreme difference in the PGDN concentrations tested.