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November 22, 2024

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.

Trimethyl benzene (mixed isomers)  

French name in the regulation: Triméthylbenzène (mélange d'isomères)
CAS : 25551-13-7

Exposure Standards in RROHS regulation

Permissible exposure values (PEV)
ppm mg/m3 f/cc Notes
TWAEV 25 123* - -
STEV - - - -
Ceiling - - - -
Carcinogenicity Sensitizer S
Simple asphyxiantPercutaneous
Prohibited useProhibited recirculation
Minimum exposureExplosion hazard
Ototoxic

TWA adjustment for unusual work schedules

III : Weekly adjustment

CNESST – Toxicological Index Service

Consult REPTOX file: Trimethyl benzene (mixed isomers)

Analysis:

Triméthylbenzène

Method: IRSST - 251-1

Sampling protocol

Sampling device:
Sampling media required:
#IRSSTDescription
2120 Activated charcoal tube 100/50 mg

Parameters:
Flow rate: Max: 0,2 L/min
TWA sampling volume: 10 L
STEL sampling volume: -

Principle: Gas chromatography with flame ionization detection (GC-FID)
Precision (%): 7,5
Minimum reported value: 62 µg
Remarks: The analysis can be done by gas chromatography coupled with mass spectrometry (GC-MS, IRSST method #369); in this case the analytical uncertainty (CVa) is 3.0%.

IRSST. "Analyse du triméthylbenzène dans l'air". Méthode 251-1. Méthodes analytiques. Montréal: IRSST, 1992.

Trimethyl benzene

Method: IRSST - 416

Sampling protocol

Sampling device:
Sampling media required:
#IRSSTDescription
2696 566AT passive dosimeter

Parameters:
Flow rate: 0,00836 L/min
TWA sampling volume: -
STEL sampling volume: -
Remarks: For the monitors, the flow must be considered as being a sampling rate.

Principle: Gas chromatography with flame ionization detection (GC-FID)
Precision (%): 5,9
Minimum reported value: 15 µg

IRSST. "Dosage des composés organiques volatils dans l'air par dosimétrie passive". Méthode 416. Non publiée.
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.