The American Conference of Governmental Industrial Hygienists (ACGIH) regularly publishes a list of substances for which they have set new or revised Threshold Limit Values (TLVs). A TLV is the airborne concentration of a chemical substance where it is believed that nearly all workers may be exposed over a working lifetime and experience no adverse health effects. TLVs may be expressed as an 8-hour time-weighted average (TWA), 15-minute short-term exposure limit (STEL), or ceiling limit.

Before adopting new or revised TLVs published by the ACGIH, WorkSafeBC reviews relevant data on health effects and the availability of validated sampling methods. WorkSafeBC also consults with stakeholders on potential implementation issues. WorkSafeBC’s existing B.C. Exposure Limits (ELs) continue to be in effect until the Board of Directors makes a decision on which new or revised ACGIH TLVs to adopt as B.C. ELs. See additional information on WorkSafeBC’s EL review process.

We are requesting stakeholder feedback on the proposed ELs for 22 substances.

(1) WorkSafeBC is proposing new or revised B.C. ELs for the following substances:

• Antimony trioxide – Production
• Antimony trioxide
• Benzene
• 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

(2) WorkSafeBC is proposing to retain the existing B.C. ELs 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

(3) For information purposes only, the existing B.C. EL is already aligned with the revised TLV for this substance:

• Epichlorohydrin

Providing feedback

Feedback on the Proposed B.C. ELs can be provided online, or via email or mail, as follows:

The consultation period ended March 14, 2025.

Please include the following information in your comments:

• Your name
• Whether you’re submitting on your own behalf or on behalf of an organization (name of your organization if you’re authorized to speak on its behalf; note that this information will be published)
• Whether you’re commenting from a worker’s perspective, an employer’s perspective, or an “other” perspective (representing a group such as a licensing or regulatory body, or a professional or industry association)
• Your level of support for the adoption of the proposed new or revised B.C. ELs in Table 1, your level of support for the retention of B.C. ELs in Table 2, as well as your level of support for the existing B.C. EL in Table 3 which is already aligned with the TLV for this substance — whether you generally agree, are generally neutral, or generally disagree
• The reasons for your level of support for the substances you are commenting on

We will send you an acknowledgment of receipt of your feedback.

Unless clarification is needed, we will not contact you about the contents of your submission.

Publication and disclosure of personal information

Please note that all comments become part of the Policy, Regulation and Research Department’s database and may be published, including the identity of organizations and those participating on behalf of organizations. The identity of those who have participated on their own behalf will be kept confidential according to the provisions of the Freedom of Information and Protection of Privacy Act. Publication by WorkSafeBC does not mean WorkSafeBC endorses the view(s) of the person making the submission.