Amendments to the Act Respecting Occupational Health and Safety: What You Need to Know

On October 1, 2025, the new Regulation respecting prevention and participation mechanisms in an establishment (the “Regulation”) came into force. It goes along with the recent amendments to the Act respecting occupational health and safety (the “AOHS”), arising from An Act to modernize the occupational health and safety regime, adopted in 2021.

In fact, on April 6, 2022, the Temporary Regime on Prevention and Participation Mechanisms (the “Temporary Regime”) was implemented by the legislator to help workplaces prepare for the introduction of a new regime. With the new regime finally adopted in October 2025, employers must now review their operations to ensure compliance with the recent legislative changes.

This new legislative framework significantly reshapes certain employer obligations, particularly with respect to the establishment of health and safety committees (“OHS Committee”), the appointment of a health and safety representative (“OHS Representative”), as well as the implementation of a prevention program or an action plan, depending on the size of the establishment.

This post aims to cover some of the key amendments to the AOHS that have been in effect since October 1, 2025. A second post will address the changes to prevention and participation mechanisms introduced by the Regulation.

1. Employer Obligations Based on the Number of Workers

Several employer obligations depend on the number of workers in a given establishment. To determine this number, workers whose services are rented or loaned to the employer must be included.^[1]

The AOHS also provides that the CNESST now has the authority to require an employer to comply with the obligations applicable to employers with 20 or more workers in the establishment, regardless of the actual number of workers present. The CNESST may impose this requirement if it considers it necessary to protect workers’ health or to ensure their safety and physical or mental well-being, or based on the criteria set out by regulation.^[2]

The prevention and participation mechanisms applicable according to the number of workers in an establishment can be summarized as follows:

Note that an employer who employs workers in more than one establishment where activities of the same nature are carried out^[3] may develop and implement a single prevention program, which must also cover establishments with fewer than 20 workers. The employer must ensure that the functions of the OHS Committee and those of the OHS Representative can be properly exercised in this context, particularly with regard to the distance between the concerned establishments.^[4]

The employer must also ensure that all activities carried out in these establishments are taken into account when developing the prevention program.

Once again, the CNESST may require the employer to develop and implement a separate prevention program for each establishment it designates if it considers it necessary to protect workers’ health or to ensure their safety and physical or mental well-being.  

(a) Obligations for Establishments with Fewer than 20 Workers

i. The Action Plan

An action plan must be developed when the employer is not required to implement a prevention program. It therefore generally applies to establishments that do not have an OHS Committee or an OHS Representative under the AOHS. The purpose of the action plan is to eliminate hazards at their source to protect the health, safety, and physical and psychological integrity of workers.^[5]

The action plan must include the following elements:

• Occupational health programs developed jointly by the Minister of Health and Social Services and the CNESST, if such a program applies to the establishment;
• Identification of risks that may affect workers’ health in the establishment, including chemical, biological, physical, ergonomic, and psychosocial risks related to work, as well as those that may affect their safety;
• Measures and priorities for action to eliminate or, if elimination is not possible, control the identified risks, giving preference to the hierarchy of preventive measures established by regulation, along with timelines for implementing these measures and priorities;
• Monitoring and maintenance measures to ensure that identified risks are eliminated or controlled;
• Identification of personal protective equipment that, while compliant with regulations, is best suited to meet the needs of the establishment’s workers;
• Training and information on occupational health and safety.

The action plan must be prepared within one year following the effective date of the amendments, so no later than October 1, 2026, or from the moment the establishment becomes subject to this obligation.^[6]

Workers are responsible for reviewing the action plan applicable to them.^[7] It falls upon the employer to ensure that the action plan is accessible to workers.

Note that, on construction sites, in the event of any conflict, the prevention program of the principal contractor takes precedence over the action plan applicable to the employer’s establishment.^[8]

ii. The Liaison Officer^[9]

When no OHS Representative is appointed in an establishment, a health and safety liaison officer (the “Liaison Officer”) is designated by the certified associations representing workers, as well as by workers not represented by an certified association, according to the nomination process they agree upon. The role of the Liaison Officer is much more limited than that of the OHS Representative.

Specifically, the Liaison Officer is responsible for:

• Cooperating with the employer to facilitate the communication of health and safety information between the employer and the workers in the establishment;
• Filing complaints with the CNESST;
• Collaborating in the development and implementation of the prevention program or action plan to be prepared and implemented by the employer by submitting written recommendations to the employer.

As to this last point, the employer must respond to a recommendation from the Liaison Officer within 30 days. If the employer fails to respond within this timeframe, the Liaison Officer may file a complaint with the CNESST.

Under the AOHS, the Liaison Officer must, within one year of being designated, participate in a training program whose content and duration will be determined by the CNESST.^[10]

The Liaison Officer may be absent from work to perform their duties, provided they inform their supervisor, and is deemed to be at work during such absences.

(b) Obligations for establishments with more than 20 workers or at the request of the CNESST

i. The Prevention Program

The employer must develop and implement a prevention program specific to each establishment with at least 20 workers during the year, or at the request of the CNESST, subject to multi-establishment groupings. If, during the year, the number of workers in an establishment falls below 20, the employer must maintain the implemented prevention program until December 31 of the following year.^[11]

The prevention program is largely similar to the action plan described above, with the addition of certain elements, namely^[12]:

• Pre-employment health examinations and health examinations during employment as required by regulation;
• The establishment and updating of a list of hazardous substances used in the establishment and contaminants that may be emitted;
• Maintaining an adequate first aid service to respond to emergencies.

The identification of the most suitable personal protective equipment to meet workers’ needs, as well as training and information programs on occupational health and safety, are determined by the OHS Committee, if one exists.

The prevention program, along with any updates, must be submitted to the OHS Committee. The employer must also submit to the CNESST, every three years from the date of the implementation of the program, using the prescribed form^[13], the action priorities established under the prevention program, the progress of the planned measures, and the follow-up on measures implemented to eliminate and control the identified risks for these priorities.^[14]

The CNESST may order an employer to modify the content of the program, notably to ensure compliance with health program requirements. The employer must then provide the modified program to the OHS Committee, the certified association, and the OHS Representative^[15].

The prevention program must be prepared within one year following the effective date of the amendments, no later than October 1, 2026, or from the moment the employer becomes subject to this obligation.^[16]

Workers are responsible for reviewing the prevention program applicable to them^[17], the employer must therefore make it accessible to workers.

Note that, on construction sites, in the event of any conflict, the prevention program of the principal contractor takes precedence over the prevention program applicable to the employer’s establishment.^[18]

ii. The Health and Safety Committee^[19]

An OHS Committee must be established in any workplace with at least 20 workers. The CNESST may also require its creation regardless of the number of workers. When several establishments share the same prevention program, a joint committee must be set up, with the option to create additional committees by agreement or at the CNESST’s request.

The functions of the OHS Committee remain similar to those provided before the amendments came into force. However, changes to the AOHS add or modify certain functions, including:

• Reviewing other elements of the prevention program, collaborating in its development, updating, and monitoring, and making recommendations to the employer;
• Making recommendations to the employer regarding whether to seek the assistance of an occupational health professional in developing the health-related components of the prevention program;
• Participating in the identification and analysis of risks that may affect workers’ health and safety and in identifying contaminants and hazardous substances present in the workplace;
• Assigning specific mandates, allowing sufficient time for their completion, to committee members, including the OHS Representative so that it can perform additional duties beyond those set out in section 90;
• Receiving and considering recommendations from the OHS Representative;
• Receiving and reviewing statistical data or any other information produced by the CNESST or any other organization.

The number of worker representatives is determined by agreement between the employer, the certified associations representing workers, and workers not represented by an certified association, according to the method they agree upon, or according to the scale set out in the Regulation. The employer designates at least one member and may appoint as many members as the total number of worker representatives.

Operating rules, including meeting frequency, are determined by agreement or, failing that, by the Regulation. Meetings are held during regular working hours unless the members agree otherwise.

Committee members must, within the timeframe set out in the Regulation, participate in training programs whose content and duration will be determined by the CNESST.^[20] They may be absent, without loss of pay, for the time necessary to attend these programs. Registration, travel, and accommodation costs are covered by the CNESST in accordance with the regulations.

iii. The Health and Safety Representative^[21]

The OHS Representative, who replaces the former prevention representative, must be designated from among the workers when a OHS Committee is in place. The OHS Representative is automatically a member of this OHS Committee. When several establishments are covered by the same prevention program, at least one OHS Representative must be designated according to terms agreed upon between the employer and the workers. The CNESST may also require the designation of an OHS Representative, even in the absence of a health and safety committee if it deems this necessary to protect health or safety.^[22]

The functions of the OHS Representative are similar to those of the former prevention representative prior to the AOHS amendments, but certain changes have been made, including:

• Making any recommendations deemed appropriate, including those concerning psychosocial risks related to work, to the health and safety committee or, failing that, to the workers or their certified association and to the employer;
• Collaborating in the development and implementation of the prevention program or action plan to be prepared and implemented by the employer by submitting written recommendations to the employer, and participating in the identification and analysis of risks that may affect workers’ health and safety and in identifying contaminants and hazardous substances present in the workplace.

The OHS Representative must inform the OHS Committee of the results of any investigation into events that caused or could have caused an accident and share with the OHS Committee the findings from the identification and analysis in which they participated.

The OHS Representative must complete training provided by the CNESST within the same timeframe and under the same conditions as the members of the OHS Committee. The number of representatives per establishment and the time allocated to their duties^[23] are determined by agreement among the members of the OHS Committee or, failing that, by the Regulation.

2. Other Key Changes to the Act Respecting Occupational Health and Safety

(a) Register of Contaminants and Hazardous Substances

The CNESST now has the authority to specify, by regulation, the circumstances and conditions under which employers will be required to maintain a register of contaminants and hazardous substances present in their establishment, as well as its content.^[24] Although the regulation is still forthcoming, it is reasonable to expect that this obligation, reflecting an increased focus on prevention and transparency in occupational health and safety, will come into effect soon. In addition to maintaining an up-to-date list of hazardous substances in the workplace, this register could include, among other things, the names of workers exposed to these substances.^[25] The procedures for transmitting the register to the CNESST will also be set out in the regulation.

(b) Joint Sector-Based Occupational Health and Safety Associations^[26]

The possibility of creating joint sector-based occupational health and safety associations, through agreements approved by the CNESST, aims to provide employers and workers with training, information, research, and advisory services tailored to the relevant sector of activity. The mandate of these associations has been expanded to include collaboration in the development and implementation of prevention programs and action plans for their member establishments. They are now also authorized to enter into partnership agreements with one another to facilitate the sharing of training and specialized services.

Our labour and employment law team will closely monitor developments related to these changes. For more information on this topic or for advice on how to manage the impact of these changes on your operations, do not hesitate to contact a member of our labour and employment law team.

*Acknowledgments to Laurence Mallette-Léonard for her assistance in drafting this post.*

^[1] Sections 58 (5) and 68 (4) of the AOHS.

^[2] Sections 58 and 68 of the AOHS.

^[3] For the purpose of determining whether the activities carried out in an establishment are of the same nature, the performance of comparable functions by workers and the conditions under which those functions are performed must, in particular, be taken into consideration. The employer must also take into account the application guide on this matter developed by the CNESST and published on its website.

^[4] Section 58.1 of the AOHS.

^[5] Section 61.1 of the AOHS.

^[6] Section 4 of the Regulation.

^[7] Section 49(1) of the AOHS.

^[8] Section 203 of the AOHS.

^[9] See sections 97.1 and following of the AOHS.

^[10] The programs have not yet been developed by the CNESST, and the training requirement is still not in effect.

^[11] Section 58 (2) of the AOSH.

^[12] Section 59 of the AOSH.

^[13] The form was not yet available at the time this post was published.

^[14] Section 60 of the AOSH. Note that this form does not exist at the time this post was published.

^[15] Section 61 of the AOSH.

^[16] Section 4 of the Regulation.

^[17] Section 49(1) of the AOSH.

^[18] Section 203 of the AOSH.

^[19] See sections 68 of the AOSH.

^[20] The programs have not yet been developed by the CNESST, and the training requirement is still not in effect.

^[21] See sections 87 and following of the AOHS.

^[22] Section 87.1 of the AOSH.

^[23] The representative may be absent from work for the time necessary to perform the duties referred to in paragraphs 2, 6 and 7 of the first paragraph of section 90, in accordance with section 92 (1) of the AOHS.

^[24] Section 223 par. 20 of the AOHS.

^[25] Section 52 of the AOHS.

^[26] See sections 98 and following of the AOHS.