Decision on the New or Revised Occupational Exposure Limits for 2008 and 2009
Background:
Each year, the American Conference of Governmental Industrial Hygienists (ACGIH) publishes a list of substances for which they have set new or revised Threshold Limit Values (TLVs). The ACGIH states that TLVs refer to airborne concentrations of chemical substances and represent conditions under which it is believed that nearly all workers may be repeatedly exposed, day after day, over a working lifetime, without adverse health effects.
In accordance with section 5.48 of the Occupational Health and Safety Regulation, these new or revised TLVs are adopted as WorkSafeBC Occupational Exposure Limits (OELs), unless otherwise determined by the Board of Directors of WorkSafeBC.
The annual 2008 and 2009 ACGIH TLVs were adopted as BC OELs prior to a review of implementation issues and stakeholder consultation. This created issues with the implementation of the new limits. Implementation issues include the practicability of implementation (i.e., can industry meet these limits?) or technical feasibility of implementation (i.e., is there a validated sampling method to measure at these new limits?).
Starting with the 2010 OELs, the Board of Directors approved a new occupational exposure limit review and adoption procedure whereby stakeholders will be consulted on potential implementation issues prior to the adoption of the annual new or revised ACGIH TLVs.
Board of Directors' Decision:
At the July 2010 meeting, the Board of Directors provided their decision on the 2008 and 2009 Occupational Exposure Limits after reviewing the results of the stakeholder consultation feedback and the internal review of the feasibility of implementation.
The 2008 and 2009 adopted OELs for substances without implementation issues are retained for aluminum metal and insoluble compounds, benomyl, ethanol, ferbam, rubber solvent and VM&P naptha.
For the other substances, the results of the stakeholder consultation and the internal review have identified that there are no validated air sampling methods or sampling devices to measure at the new or revised TLVs. For sulfur dioxide, there are sampling issues as well as practicability of implementation issues.
After considering these issues, the Board of Directors decided to reinstate the former exposure limits that were in place prior to the revision by ACGIH until the implementation issues can be resolved for these substances.
The following WorkSafeBC OELs are assigned to these 2008 substances:
| Substances | WorkSafeBC Occupational Exposure Limit | ||
|---|---|---|---|
| 8-hour Time-Weighted Average Limit | Short-Term Exposure Limit | Ceiling Limit | |
| Butenes, all isomers, including isobutene | No previous limit | No previous limit | No previous limit |
| Carbaryl | 5 mg/m3 | ||
| Indene | 10 ppm | ||
| Iodine | 0.1 ppm | ||
| Iodides | No previous limit | No previous limit | No previous limit |
| Natural rubber latex, as total proteins, inhalable | 0.001 mg/m3 | ||
| 1,1,1,2-tetrachloro-2,2-difluoroethane | 500 ppm | ||
| Thiram | 1 mg/m3 | ||
| Trimellitic anhydride | 0.04 mg/m3 | ||
The following WorkSafeBC OELs are assigned to these 2009 substances:
| Substances | WorkSafeBC Occupational Exposure Limit | ||
|---|---|---|---|
| 8-hour Time-Weighted Average Limit | Short-Term Exposure Limit | Ceiling Limit | |
| Beryllium and compounds | 0.002 mg/m3 | 0.01 mg/m3 | |
| Dibutyl phosphate | 1 ppm | 2 ppm | |
| Diethanoloamine | 2 mg/m3 | ||
| Endosulfan | 0.1 mg/m3 | ||
| Ethyleneimine | 0.5 ppm | ||
| Methyl parathion | 0.2 mg/m3 | ||
| Propyleneimine | 2 ppm | ||
| Sulfur dioxide | 2 ppm | 5 ppm | |
| Sulprofos | 1 mg/m3 | ||
The following two substances are removed from the Table of OELs for Excluded Substances in Policy R5.48-1 because the ACGIH TLVs are now more protective and there are no implementation issues. The ACGIH TLVs are assigned to the OELs for these substances:
| Hydroquinone | 8 hour TWA 1 mg/m3 |
| Polyvinyl chloride | 8 hour TWA 1 mg/m3 (respirable fraction) |
These changes are reflected in the updated Table of OELs for Excluded Substances in Policy R5.48-1 [link missing].