Decision on the New and Revised B.C. Exposure Limits based on the 2021, 2022, 2023, and 2024 ACGIH TLVs for Selected Chemical Substances
At its April 2025 meeting, WorkSafeBC’s Board of Directors (BOD) approved the adoption of the 2021, 2022, 2023, and 2024 new and revised American Conference of Governmental Industrial Hygienists Threshold Limit Values (ACGIH TLVs) for the following selected chemical substances.
- Antimony trioxide – Production
- Antimony trioxide
- Cumene
- Dipropylene glycol methyl ether (also known as “bis-(2-Methoxypropyl) ether (DPGME)”)
- Dipropylene glycol methyl ether (DPGME)
- Hexane, all isomers, except n-Hexane
- Hexane (Commercial, >54% n-Hexane) and the branched hexane isomers
- Hexane (Commercial, <54% n-Hexane)
- Branched Hexane Isomers
- sec-Hexyl acetate
- Isopropylamine
- Isopropyl ether
- Methylcyclohexane
- Mica
- Trimethyl benzene (mixed isomers)
- Trimethyl benzene, isomers
- Xylene (o, m & p isomers)
- Xylene, all isomers
In addition, Epichlorohydrin’s revised ACGIH TLV is already the same as the existing B.C. exposure limit.
Effective June 20, 2025, these substances will be removed from the Table of Exposure Limits for Excluded Substances in Policy R5.48-1 of the Prevention Manual and the ACGIH TLVs will be assigned as B.C. exposure limits:
|
Substance |
B.C. exposure limits |
||
|---|---|---|---|
|
8-hour time-weighted average limit |
Short-term exposure limit |
Ceiling limit |
|
|
Antimony trioxide – Production |
--- |
--- |
--- |
|
Antimony trioxide |
0.02 mg/m3 |
--- |
--- |
|
Cumene |
5 ppm |
--- |
--- |
|
Dipropylene glycol methyl ether (also known as “bis-(2-Methoxypropyl) ether (DPGME)”) |
--- |
--- |
--- |
|
Dipropylene glycol methyl ether (DPGME) |
50 ppm |
--- |
--- |
|
Epichlorohydrin |
0.1 ppm |
--- |
--- |
|
Hexane, all isomers, except n-Hexane |
--- |
--- |
--- |
|
Hexane (Commercial, <54% n-Hexane) and the branched hexane isomers |
--- |
--- |
--- |
|
Hexane (Commercial, <54% n-Hexane) |
100 ppm |
--- |
--- |
|
Branched Hexane Isomers |
200 ppm |
--- |
--- |
|
sec-Hexyl acetate |
20 ppm |
50 ppm |
--- |
|
Isopropylamine |
2 ppm |
5 ppm |
--- |
|
Isopropyl ether |
20 ppm |
--- |
--- |
|
Methylcyclohexane |
100 ppm |
--- |
--- |
|
Mica |
0.1 mg/m3, |
--- |
--- |
|
Trimethyl benzene (mixed isomers) |
--- |
--- |
--- |
|
Trimethyl benzene, isomers |
10 ppm |
--- |
--- |
|
Xylene (o, m & p isomers) |
--- |
--- |
--- |
|
Xylene, all isomers |
20 ppm |
--- |
--- |
Due to sampling issues, the BOD decided to not adopt the new or revised ACGIH TLVs for the following substances:
- tert-Butyl hydroperoxide
- Glycidyl methacrylate
- Ketene
- 2-Methyl-2-butene
- o-Methylcyclohexanone
- Methylcyclohexanone, all isomers
- Perchloryl fluoride
- Phenylethyl alcohol
- Propionitrile
- Triclosan
For these substances, the existing B.C. exposure limits will be maintained on the Table of Exposure Limits for Excluded Substances in Policy R5.48-1 of the Prevention Manual.
A decision on the adoption of the new or revised ACGIH TLV for benzene will be postponed until WorkSafeBC has done further analysis and review of the peer-reviewed health studies as well as the reported sampling and implementation issues. As such, benzene’s existing 8-hour time-weighted average limit of 0.5 ppm and 15-minute short-term exposure limit of 2.5 ppm will remain at this time.
WorkSafeBC will continue to monitor the availability of sampling methods for all of these substances, as well as to work on ongoing initiatives to develop, validate, and implement sampling methods.