Current Intelligence Bulletin 66: Derivation of Immediately Dangerous to Life or Health (IDLH) Values

The intent of this document is to update the Immediately Dangerous to Life or Health (IDLH) methodology used by NIOSH to develop IDLH values based on contemporary risk assessment practices and to increase the transparency behind their derivation. The increased transparency will provide occupational health professionals, risk managers, and emergency response personnel additional information that can be applied to improve characterization of the hazards of high concentrations of airborne contaminants. This will also facilitate a more informed decision-making process for the selection of respirators and establishment of risk management plans for non-routine work practices and emergency preparedness plans capable of better protecting workers.