OHS Code Explanation Guide

Published Date: July 01, 2009
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Part 4 Chemical Hazards, Biological Hazards and Harmful Substances


  • OEL changes: Occupational Exposure Limits (OELs) were revised for nearly 150 substances (see Schedule 1, Table 2). The revised OELs are based largely on the 2006 American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Values (TLVs) for Chemical Substances.
  • Significant changes: Ten substances have OELs that differ significantly from the ACGIH TLVs: acetone, benzene, coal dust, cobalt, formaldehyde, manganese, ozone, propane, styrene and wood dust.
  • Slight changes: Three substances have OELs that differ slightly from the ACGIH TLVs: acetic anhydride, hydrogen sulphide and toluene 2,4-diisocyanate.
  • Missing TLVs: Four substances for which ACGIH did not have TLVs when this Part was prepared: polymethylene polyphenyl isocyanate, refractory ceramic fibres, sulphur and 1,1,1-trifluoro-2,2-dichloroethane.
  • Section 16 prohibits a worker being exposed to a chemical substance at a concentration exceeding its ceiling limit at any time and to a concentration that is immediately dangerous to life and health.
  • Section 18 requires employers to ensure that OELs are adjusted for work shifts longer than eight hours.
  • Sections 21 and 22 require employers to assess worker exposure to harmful substances and sets monitoring requirements.
  • Section 26 requires employers to prepare a code of practice governing the storage, handling, use and disposal of any substance present at a work site that is listed in Table 1 of Schedule 1. (Section 8 of the OHS Regulation requires that procedures specified by a code of practice be in writing and available to workers).
  • Sections 28 through 43 consolidate the rules regarding asbestos, silica and coal dust. The term “restricted area” is classified, based on the substances’ OELs.
  • Sections 32 through 34 restrict the use of asbestos in buildings. These provisions have been transferred from the Alberta Building Code. The restrictions will be removed from the Alberta Building Code the next time it is revised.
  • Section 37 clarifies the requirement that employers ensure asbestos workers working in restricted areas have successfully completed an approved asbestos course.
  • Section 39 allows employers to use crystalline silica for abrasive blasting. However, the employer must, if reasonably practicable, ensure that crystalline silica is replaced with a less harmful substance.
  • Section 41 requires that employers develop an exposure control plan for lead for work sites where workers may be adversely affected by lead exposure.
  • Section 43 describes the corresponding medical monitoring requirements. (Section 8 of the OHS Regulation requires that the plan be in writing and available to workers).