Immediately Dangerous to Life or Health (IDLH) 10 :
An atmosphere that poses an immediate threat to life, would cause irreversible adverse health effects, or would impair an individual's ability to escape from a dangerous atmosphere
Environmental Health and Safety, Glossary, University of Chicago, Illinois, USA 2010. http://safety.uchicago.edu/tools/glossary.shtml, (Ergo - Amer) {753}
University of California (Environmental Health & Safety), Safety & Industrial Hygiene Glossary of Terms, Riverside, CA, USA 2010. http://ehs.ucr.edu/safety/glossary.html, (IndHygS - Amer) {500}