IRSST - Institut de recherche Robert-Sauvé en santé et en sécurité du travail

Hydrogen fluoride

French name in the regulation: Fluorure d'hydrogène
CAS : 7664-39-3
Synonyms: Hydrofluoric acid; Fluoric acid

Exposure Standards in RROHS regulation

Permissible exposure values (PEV)
ppm mg/m3 f/cc Notes
TWAEV - - - -
STEV - - - -
Ceiling 3 2,6 - -
Simple asphyxiant Percutaneous
Minimum exposure Sensitizer
Prohibited use Prohibited recirculation

TWA adjustment for unusual work schedules

1A : No adjustment

CNESST – Toxicological Index Service

Consult REPTOX file: Hydrogen fluoride


Fluorure d'hydrogène (exprimé en F)

Recommended method by the IRSST:
Method: NIOSH - 7902
Sampling device: Mixed cellulose ester filter followed by a pretreated cellulose pad
Flow rate: 1-2 L/min
TWA sampling volume: 800 L
STEL sampling volume: -
Remarks: Contact the IRSST before sampling. Recommended volume between 12 and 800 litres.
Principle: Ion specific electrode (SE)
NIOSH Manual of Analytical Methods. 4th ed. Method 7902 : Fluorides, Aerosol and Gas. NIOSH, 1994.
Following the amendment of Appendix 1 of the Quebec Regulation respecting occupational health and safety (RSST, RLRQ, c. S-2.1, r. 13), part of Quebec Occupational Health and Safety Act, which came into effect on March 26, 2020, the TWAEV, STEL and Ceiling values for certain substances are now expressed in ppm. For these substances, the IRSST performed the conversion calculations to express these TWAEV, TWA and Ceiling values in mg/m3, which thus appears in its Sampling Guide for Air Contaminants in the Workplace (Guide d'échantillonnage des contaminants de l'air en milieu de travail ) and the associated Substance Data Sheets. However, it is imperative to refer to the values expressed in the RSST which are legally binding.