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

According to Decree 280-2024 published on February 28, 2024, in the Gazette officielle du Québec, the amendment to the Appendix 1 of the Regulation respecting occupational health and safety (RSST, RLRQ, c. S-2.1, r. 13) will come into force on March 14, 2024. These regulatory changes have not yet been incorporated into the current Substance Data Sheets of the Sampling Guide for Air Contaminants in the Workplace. An update is currently underway and will be available as soon as possible. Consequently, the information contained in the data sheets of substances modified or added in Decree 280-2024 is partially inaccurate or incomplete. Please consult our infoLABO (in French only) for more details. Please contact our client service: [email protected] for further information.

Asbestos, Amosite

French name in the regulation: Amiante, Amosite
CAS : 12172-73-5
Synonyms: Mysorite

Exposure Standards in RROHS regulation

Permissible exposure values (PEV)
ppm mg/m3 f/cc Notes
TWAEV - - 0,1 2a , 2b , 3
STEV - - - -
Ceiling - - - -
Simple asphyxiant Percutaneous
Minimum exposure  Sensitizer
Prohibited use Prohibited recirculation
Carcinogenicity C1

TWA adjustment for unusual work schedules

III : Weekly adjustment

CNESST – Toxicological Index Service

Consult REPTOX file: Asbestos, Amosite

Analysis:

Numération de fibres

Method: IRSST - 243
Sampling device:
Sampling media required:
#IRSSTDescription
918 Cassette with conductive extension and MCE, 25 mm, 0.8 µm

Parameters:
Flow rate: 0,5-16 L/min
TWA sampling volume: 400 L
STEL sampling volume: -
Remarks: Open cassette sampling. A flow rate not exceeding 2.5 L/min is recommended to determine an average concentration. Supply at least 2 blanks per series of samples or 10% of sample total, whichever is highest. Send the samples in a cardboard box supplied by the IRSST (#3010). In relatively clean atmospheres, where the fiber concentration is less than 0.1 fibres/mL, use larger sampling volumes (3000 to 10000L) to obtain quantifiable densities.
Principle: Phase contrast optical microscopy (PCM)
Remarks: The method applies to the counting of all fibres whose refractive index is compatible with the mounting solution. The minimum reported value is 9 fibres/mm². Characterization of the fibres in bulk samples or in deposited dusts is done using method 244. An analysis using a transmission electron microscopy (TEM) method may be required for some materials containing fine asbestos fibres, for example floor tiles.
IRSST. "Numération des fibres". Méthode 243. Méthodes analytiques. Montréal: IRSST, 2022.
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.