July 23, 2020

NIOSH Publishes IDLH Values for Bromine Trifluoride, Other Chemicals

NIOSH has published new immediately dangerous to life or health (IDLH) values for the chemicals bromine trifluoride, chlorine trifluoride, and ethylene dibromide. The agency’s IDLH values are established to ensure workers’ ability to escape from a contaminated environment in the event that their respiratory protection equipment fails. IDLH values are also intended to represent a maximum level above which workers should not be exposed without highly reliable respiratory protection. Each new NIOSH “IDLH value profile” is intended to summarize the health hazards of acute exposures to high airborne concentrations of a chemical and discuss the rationale for the chemical’s IDLH value.

NIOSH set the IDLH value for bromine trifluoride (BrF3) at 12 ppm (67 mg/m3). Because data were inadequate to directly derive an IDLH value for bromine trifluoride, the agency used data from studies with chlorine trifluoride—a chemical with similar structure, reaction mechanisms, and potency—to develop the value for BrF3. The IDLH value for chlorine trifluoride is set at 12 ppm (45 mg/m3), and is based on data on eye irritation in rats exposed to the chemical at a concentration of 480 ppm for five minutes, which researchers determined to impair escape. The IDLH value for ethylene dibromide, 46 ppm (354 mg/m3), is based on a 36-minute no observed adverse effect level (NOAEL) for lethality value of 400 ppm in rats.

NIOSH updated its method for determining IDLH values in 2013 via Current Intelligence Bulletin 66: Derivation of Immediately Dangerous to Life or Health (IDLH) Values, or CIB 66. The document notes that occupational health and safety professionals have incorporated IDLH values into risk management plans for operations in high-risk environments such as confined spaces, and in guidance for emergency responders.

For more information on IDLH values, visit the NIOSH website​.​​​​​​