Sodium hydroxide

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.

Sodium hydroxide

French name in the regulation: Sodium, hydroxyde de

CAS : 1310-73-2

Synonyms: Caustic soda

Exposure Standards in RROHS regulation

Permissible exposure values (PEV)

	ppm	mg/m³	f/cc	Notes
TWAEV	-	-	-	-
STEV	-	-	-	-
Ceiling	-	2	-	-

Carcinogenicity		Sensitizer
Simple asphyxiant		Percutaneous
Prohibited use		Prohibited recirculation
Minimum exposure		Explosion hazard
Ototoxic

TWA adjustment for unusual work schedules

1A : No adjustment

CNESST – Toxicological Index Service

Consult REPTOX file: Sodium hydroxide

Analysis:

Sodium (exprimé en Na)

Recommended method by the IRSST:

Method: NIOSH - 7303

Sampling protocol

Sampling device: Mixed cellulose ester filter
Parameters:
Flow rate: 4 L/min
TWA sampling volume: -
STEL sampling volume: 60 L
Remarks: This substance is not analyzed by our laboratories. It might be possible that the analysis be performed by another laboratory. Please contact the IRSST before sampling. Specific sampling for this substance must be carried out.

Analytical protocol

Principle: Inductively coupled plasma-optical emission spectrometer (ICP-OES)
Remarks: This method allow to analyze the chemical element present in the sample without distinguish its chemical form. The analytical results are expressed as total sodium A stoichiometric factor must be applied.

Reference

NIOSH Manual of Analytical Methods, 4rd ed., ELEMENTS by ICP (Hot Block/HCl/HNO3 Digestion), Cincinnati, NIOSH, 2003