Immediately Dangerous to Life and Health Limits (IDLHs)

IDLH values are workplace exposure limits that are meant to protect workers when they are exposed to a toxicPoisonous; can injure or kill people or other organisms. chemical in the course of their work.

Note: If available, IDLH values are shown on chemical datasheets in the Physical Properties section.

What are IDLHs?

The National Institute of Occupational Safety and Health (NIOSHNational Institute for Occupational Safety and Health (www.cdc.gov/niosh). The federal agency responsible for conducting research and making recommendations for the prevention of work-related disease and injury. NIOSH is part of the Centers for Disease Control and Prevention (CDC).) defines an immediately dangerous to life or health condition as a situation "that poses a threat of exposure to airborne contaminants when that exposure is likely to cause death or immediate or delayed permanent adverse health effects or prevent escape from such an environment." (External link.)

The IDLH limit represents the concentrationThe amount of a chemical present in a given weight or volume of air. Concentration of a gas in air may be expressed in units such as parts per million (by volume) or milligrams per cubic meter. of a chemical in the air to which healthy adult workers could be exposed (if their respirators fail) without suffering permanent or escape-impairing health effects.

For More Information

  • How are IDLHs chosen?How are IDLHs chosen?

    IDLHImmediately Dangerous to Life and Health limits, levels of concern for adult workers; estimate of the highest concentration in air from which escape is possible without permanent injury (if their respirators fail). IDLHs are established by the National Institute for Occupational Safety and Health (www.cdc.gov/niosh). limits are derived by NIOSHNational Institute for Occupational Safety and Health (www.cdc.gov/niosh). The federal agency responsible for conducting research and making recommendations for the prevention of work-related disease and injury. NIOSH is part of the Centers for Disease Control and Prevention (CDC). based on animal and human data. Two factors are considered when establishing IDLH limits. Workers must be able to escape from the environment where they are exposed to hazardous chemicals without suffering:

    • Permanent health damage.
    • Severe eye or respiratory tract irritation (or other conditions) that might impair their ability to escape.

    To find out more about the IDLH development process, go to the External link.Ìý·É±ð²ú²õ¾±³Ù±ð.

  • What substances have IDLHs?What substances have IDLHs?

    There are more than 380 substances with IDLHImmediately Dangerous to Life and Health limits, levels of concern for adult workers; estimate of the highest concentration in air from which escape is possible without permanent injury (if their respirators fail). IDLHs are established by the National Institute for Occupational Safety and Health (www.cdc.gov/niosh). limits. See the External link..

    You can also search in CAMEO 365betÓéÀÖ or the External link. to find IDLH values for specific substance.

  • How should IDLHs be used?How should IDLHs be used?

    IDLHImmediately Dangerous to Life and Health limits, levels of concern for adult workers; estimate of the highest concentration in air from which escape is possible without permanent injury (if their respirators fail). IDLHs are established by the National Institute for Occupational Safety and Health (www.cdc.gov/niosh). limits were created mainly to assist in making decisions regarding respirator use. Above the IDLH, only supplied air respirators should be used; below the IDLH, air purifying respirators may be used, if appropriate.

    Until 1994, an exposure duration of 30 minutes was associated with the IDLH. However, the current definition has no exposure duration associated with it; workers should not be in an IDLH environment for any length of time unless they are equipped and protected to be in that environment.

IDLH Information Online

  • External link. Read all about IDLHs on this NIOSH site, which contains a list of current IDLHs and details about IDLH development.
  • External link. See the current list of chemicals with IDLHs (and an explanation of how the value for each chemical was derived) on this NIOSH site.