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Part of OHS Code review

OHS Code review - Occupational Exposure Limits survey

Help update Alberta’s OHS Code by providing your input for potential changes to occupational exposure limits.

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OHS Code review

Introduction

The Government of Alberta continues to review the Occupational Health and Safety (OHS) Code.

The OHS Code contains detailed technical requirements to protect worker health and safety at work sites. In 2020, the Government of Alberta developed a plan to update the OHS legislation, which aims to:

  • Protect the health and safety of workers in Alberta.
  • Make rules easy to understand and apply.
  • Align Alberta’s OHS legislation with other Canadian jurisdictions.
  • Empower work site parties to carry out their responsibilities for health and safety according to their level of authority and control.
  • Correct errors, reduce duplication and conflict in requirements.
  • Reduce unnecessary administrative burden.

This confidential survey will obtain input on proposed changes to occupational exposure limits (OELs). Your input is vital to the review process and will inform recommendations for OHS Code changes.

Section 16 of the OHS Code requires an employer to ensure that workers exposure to a substance does not exceed its occupational exposure limit (OEL) listed in Schedule 1, Table 2. Currently, there are approximately 800 OELs listed in the table.

Most OELs in the OHS Code are based on Threshold Limit Values (TLVs) developed by the American Conference of Governmental Industrial Hygienists (ACGIH). The current OELs in the OHS Code are based on the 2006 TLVs with some exceptions. Each year, ACGIH reviews a number of TLVs and makes revisions based on current science and knowledge regarding the health effects of exposure to the substance. In Alberta, the OHS legislation does not automatically adopt the most current TLVs; rather a process of review and consultation is followed to ensure the OELs are appropriate for Alberta workplaces.  

Technical review was done with the assistance of a technical working group with representation from employers, workers and technical experts. It is proposed to update OELs to reflect the 2024 TLVs, with some exceptions. Some amendments to Part 4 requirements are also proposed to reflect updates in terminology and measurement.

This survey includes general questions related to proposed updates to OELs as well as specific questions regarding updates to OELs for benzene, hydrogen sulphide, and diesel particulate matter. The survey also includes questions on updating referenced technical standards and new and updated terminology.

Additional surveys on proposed changes to other parts of the OHS Code are also available on the following topics:

  • Part 36 (Mining).
  • Part 40 (Utility Workers – Electrical).
  • Miscellaneous Changes and Approach to Referencing Technical Standards.
  • OHS Harmonization Initiatives

Please see the OHS Code review webpage for more information and to participate.

If you have questions regarding the survey, or the OHS Code review in general, please contact [email protected] for assistance. 

Survey

All fields are required unless otherwise indicated.

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Survey details

If you will be completing the survey on behalf of an organization, a PDF copy of the questionnaire can be downloaded for your reference while consolidating your feedback.

After compiling your organization’s feedback, please enter your organization’s response as a survey submission. This ensures that your input will be accurately captured and reflected in the data set.

This form will take 30 to 40 minutes to complete and closes July 8, 2026. For optimal functionality, it is recommended to complete this survey on a desktop, not on a mobile phone.

Important: Please note that progress cannot be saved. Closing this window or navigating away will clear all responses. Please allow sufficient time to complete the survey in a single, uninterrupted session.

Section 1: Demographic information

2. I am providing input on behalf of:
4. The group I am providing input on behalf of is my:
6. Approximately how many people in Alberta are represented by your group?

Section 2: Occupational exposure limits

Occupational Exposure Limits (Table 2, Schedule 1; Section 18)
Section 16 of the OHS Code requires an employer to ensure workers are not exposed to a substance above its occupational exposure limit. Currently, occupational exposure limits in Table 2, Schedule 1 the OHS Code reflect 2006 American Conference of Governmental Industrial Hygienists (ACGIH) Threshold Limit Values (TLVs) with some exceptions.

In section 18 of the OHS Code, if a worker may be exposed to a substances in Table 2, Schedule 1 during a single work shift which is longer than eight hours, the occupational exposure limit must be adjusted using the listed formula (“Brief and Scala” method). The adjustment requirement does not apply to a substance for which “3” (do not adjust) appears in the substance interaction column in Table 2, Schedule 1.

Change A:
To improve health and safety, it is proposed to update occupational exposure limits to reflect 2024 ACGIH TVLs with some exceptions.

This includes adoption of thoracic and inhalable size selective notations, following ACGIH conventions for measurement type (ppm versus mg/m3), and removing duplicate entries in Table 2, Schedule 1.

This does not include the adoption of surface limits, as well as inhalable fraction and vapour limits. To see values which are proposed to be changed, please see the printable PFD here .
Please note:

  • OELs with no proposed changes are not included in the table, unless it is a deviation from the ACGIH TVLs.
  • Exceptions that deviate from the 2024 TLVs are noted in red font in the table.
Why are modifications necessary for the proposed changes (Change A)?
What is the main reason you disagree with the proposed changes (Change A)?

Change B:
To improve health and safety, it is proposed to remove the “do not adjust” notation in Table 2, Schedule 1. The ”do not adjust” notation ties back to the requirement in section 18 of the OHS Code which requires employers to adjust OELs when work shifts are longer than 8 hours. This is because, most OELs are based on a time weighted exposure over an 8 hour work shift.

The ”do not adjust” notation is applied to some OELs that have health effects based on irritation alone. However, this approach to not adjust for some substances is not appropriate from a technical or health and safety perspective and information on health effects continues to evolve so health effects may not be based on irritation alone. This change will also require subsection 18(2) in Part 4 Chemical Hazards, Biological Hazards and Harmful Substances to be repealed reference to the notation to align.

Why are modifications necessary for the proposed changes to section Table 2, Schedule 1 (Change B)?
What is the main reason you disagree with the proposed changes to Table 2, Schedule 1 (Change B)?

Occupational Exposure Limits (Table 2, Schedule 1)

Occupational Exposure Limits (Table 2, Schedule 1)
The following questions are related to proposed changes to specific OELs.

Question A:
Currently, the OEL for benzene is 0.5 ppm (8-hour) and 2.5 ppm (15-minute).

To improve health and safety, it is proposed to change the OEL for benzene from: 0.5 ppm 8-hour OEL and 2.5 15-minute OEL to a 0.2 ppm 8-hour OEL. This value is different from the 2024 ACGIH TLV and reflects the current European limit for benzene.

Why are modifications necessary for the proposed changes to Table 2, Schedule 1?
What is the main reason you disagree with the proposed change to Table 2, Schedule 1?

Question B:
Currently the OEL for hydrogen sulphide is 10 ppm (8-hour) and 15 ppm (ceiling).

To improve health and safety, it is proposed to change the occupational exposure limit for hydrogen sulphide from 10 ppm 8-hour OEL and 15 ppm ceiling OEL to a 10 ppm ceiling OEL. This value is different from the 2024 ACGIH TLV and reflects the current British Columbia OEL for hydrogen sulphide.

Why are modifications necessary for the proposed changes to Table 2, Schedule 1?
What is the main reason you disagree with the proposed change to Table 2, Schedule 1?

Question C:
Currently, there is no OEL for diesel particulate matter in the OHS Code.

Do you agree with the adoption of a new OEL for diesel particulate matter of 0.1 mg/m3 based on elemental carbon. This value reflects the current British Columbia limit for diesel particulate matter for mining work sites.

Why are modifications necessary for the proposed changes to Table 2, Schedule 1?
What is the main reason you disagree with the proposed change to Table 2, Schedule 1?

Occupational Exposure Limits (Prologue to Table 2)

Occupational Exposure Limits (Prologue to Table 2)
There is wording before Table 2 in Schedule 1 which currently provides an explanation of terms used in Table 2 and explains the meaning of the notations and substance interactions.

To correct an error, it is proposed to adjust the “ppm” explanation from “ppm (parts per million) means parts of a vapour or gas by volume at standard conditions (25ºC and an absolute barometric pressure of 101.3 kilopascals) per parts of contaminated air by volume at ambient work site conditions” to “ppm (parts per million) means parts of a vapour or gas in air (by volume) per million parts of air (by volume)”.

Why are modifications necessary for the proposed changes to the Table 2 Prologue?
What is the main reason you disagree with the proposed change to the Table 2 Prologue?

Occupational Exposure Limits (Section 16)

Occupational Exposure Limits (Section 16)
Currently, an employer must ensure worker exposure to a substance listed in Table 2, Schedule 1 is kept as low as reasonably achievable and does not exceed its OEL. The amended OEL for coal dust came into effect on July 1, 2010.

If there is no OEL established for a harmful substance present at a work site, the employer must ensure worker exposure is kept as low as is reasonably achievable.

A worker must not be exposed to a substance at a level exceeding its ceiling limit list in Table 2, Schedule 1 at any time.

If there is no 15-minute OEL or ceiling OEL for a substance listed in Table 2, Schedule 1, the employer must comply with the 8-hour OEL and ensure worker exposure does not exceed three times the 8-hour OEL for more than a total of 30 minutes in a 24-hour period and five times the 8-hour OEL or the concentration which is immediately dangerous to life and health, whichever is lower.

Change A:
To correct an error and ensure 15-minute OELs are applied correctly, it is proposed to add a new section on the rules for applying a 15-minute OEL. This provision was previously in the 2007 OHS Code and was erroneously removed in the 2009 edition.

If a worker is exposed at a concentration exceeding the 8-hour OEL but less than the 15-minute OEL:

  • The employer must ensure each 15-minute period of exposure is followed by at least 60 minutes where the exposure is at or below the 8-hour OEL,
  • The worker may not be subjected to more than four of the 15-minutes of exposure in a workday, and
  • The 8-hour OEL may not be exceeded.
Why are modifications necessary for the proposed changes (Change A)?
What is the main reason you disagree with the proposed changes (Change A)?

Change B:
To clarify employer responsibilities, it is proposed to add an employer responsibility to ensure a worker is not exposed above a ceiling OEL.

Why are modifications necessary for the proposed changes to section 16 (Change B)?
What is the main reason you disagree with the proposed changes to section 16 (Change B)?

Occupational Exposure Limits (Section 20)

Occupational Exposure Limits (Section 20)
Currently, section 20 prescribes the measurement methods that must be used when determining compliance with an OEL.

If there is no analytical method or procedure for a substance, an employer may use a continuous reading direct reading instrument to measure airborne concentrations to comply with an OEL as long as the instrument is used, calibrated and maintained according to the manufacturer’s specifications.

An employer must ensure the person conducting airborne measurements is competent to do so.

If a person is counting asbestos fibres, they must apply NIOSH Method 7400 and only to the particles that meet the size criteria for fibres.

To reflect best practices for health and safety, it is proposed to update the referenced technical standards for conducting measurements of airborne concentrations to the most current versions:

  • NIOSH Manual of Analytical Methods, 4th Edition, unless it has been updated in the 5th Edition, published by the United States Department of Health and Human Services, as amended up to and including the 3rd supplement,
  • Sampling and Analytical Methods published by the United States Occupational Safety and Health Administration,
  • Methods for the Determination of Hazardous Substances guidance published by the Health and Safety Executive of Great Britain,
  • Environmental Measurements and Modelling Methods published by the United States Environmental Protection Agency (EPA),
  • Sampling Guide for Air Contaminants in the Workplace, 8th edition, version 8.1 published by the Institut de recherché Robert-Sauvé en santé et en sécurité du travail (IRSST),
  • ISO Standards and Guides of Air Quality published by ISO Technical Committee TC146
  • Analyses of Hazardous Substances in Air published by DFG Deutsche Forschungsgemeinschaft – Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area.
Why are modifications necessary for the proposed changes to section 20?
What is the main reason you disagree with the proposed change to section 20?

Occupational Exposure Limits (Definitions)

Occupational Exposure Limits (Definitions)
The following questions are regarding new or proposed changes to definitions in the OHS Code.

Fibre
Currently, “fibre” means a particulate material with:
(a) a diameter equal to or less than 3 micrometres;
(b) a length equal to or greater than 5 micrometres; and
(c) a length to diameter ratio equal to or greater than 3 to 1.

To clarify that this definition applies only to the use of “fibre” in Part 4 of the OHS Code, it is proposed to change the definition to:
“fibre” in Part 4 means a particulate material with
(a) a diameter equal to or less than 3 micrometres;
(b) a length equal to or greater than 5 micrometres; and
(c) a length to diameter ratio equal to or greater than 3 to 1.

Occupational Exposure Limits (Definitions - Inhalable)

Inhalable
Currently, there is no definition for “inhalable” in the OHS Code. To reflect the proposed adoption of inhalable limits, it is proposed to add a new definition for “inhalable”.

“Inhalable” means airborne particulate that meets the American Conference on Governmental Industrial Hygienists and International Organization for Standardization/European Standardization Committee inhalable size-selection curve and has a 50 percent cut-point at 100 micron aerodynamic diameter.

Occupational Exposure Limits (Definitions - Respirable)

Respirable Particulate
Currently, “respirable particulate” means airborne particulate collected and analyzed using NIOSH Method 0600, Particulates Not Otherwise Regulated, Respirable.

To be consistent with international definitions, it is proposed to revise the definition of “respirable”:
“Respirable” means an airborne particulate that meets the American Conference on Governmental Hygienists and International Organization for Standardization/European Standardization Committee respirable size-selection curve and has a 50 percent cut-point of 4 micron aerodynamic diameter.

Occupational Exposure Limits (Definitions - Thoracic)

Thoracic
Currently, there is no definition for “thoracic” in the OHS Code.

To reflect proposed adoption of thoracic limits, it is proposed to add a new definition for “thoracic”:
“Thoracic” means an airborne particulate that meets the American Conference of Governmental Industrial Hygienists and International Organization for Standardization/European Standardization Committee thoracic size-selection curve and has a 50 percent cut-point at 10 micron aerodynamic diameter.

Section 3: Conclusion

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