Environmental chemistry and management of hydrazine

The recent use of 70% hydrazine-water fuel in the F-16 emergency power unit (EPU) presents problems for organizations responsible for protection of personnel and the environment because of the worldwide deployment of this aircraft and the requirement for fuel handling in a flightline environment. Hydrazine has a low vapor pressure (14 mm Hg at 25 degrees C) but still evaporation rates (16-100 mg/cm2h) from liquid pools are sufficient to generate hazardous atmospheric concentrations greater than the permissible exposure level (3 ppm) up to 2 km downwind under worst-case meteorological conditions (F Stability). In contrast to the general feeling that hydrazine degrades in the presence of atmospheric oxygen, studies show hydrazine is relatively stable in both air (t1/2 approximately 6 h) and oxygenated aqueous solutions (t1/2 approximately 5 d). The toxicity and stable character of hydrazine in the environment required quick and thorough management of any accidental spills to preclude hazards to personnel and serious environmental degradation. The Air Force has established comprehensive containment and treatment procedures which will be used in the event of inadvertent releases of hydrazine from the EPU or during handling or transport of the bulk fuel. The simple spill management procedures used to support the F-16 aircraft EPU are described.