 For aerospace personnel, the USAF uses an emergency exposure guideline, developed by the National Academy of Science Committee on Toxicology, which is utilized for non-routine exposures of the general public and is called the Short-Term Public Emergency Exposure Guideline (SPEGL).The SPEGL, which does not apply to occupational exposures, is defined as the acceptable peak concentration for unpredicted, single, short-term emergency exposures of the general public and represents rare exposures in a worker's lifetime.For hydrazine the 1-hour SPEGL is 2 ppm, with a 24-hour SPEGL of 0.08 ppm.