Immediately Dangerous to Life and Health (IDLH) value
The National Institute for Occupational Safety and Health (NIOSH) uses Immediately Dangerous to Life and Health (IDLH) values as respirator selection criteria. The Occupational Safety and Health Administration (OSHA) defines an IDLH as an atmospheric concentration of any toxic, corrosive or asphyxiant substance that poses an immediate threat to life or that would cause irreversible or delayed adverse health effects or would interfere with an individual’s ability to escape from a dangerous atmosphere. http://www.cdc.gov/niosh/idlh/idlhintr.html (Opens in new window).