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MLITSD Occupational Hygiene Inspections – Frequently Asked Questions

worker making notes .

The MLITSD is conducting two occupational hygiene focused campaigns from April 1, 2024, to March 31, 2025, with inspections beginning July 2, 2024. Find answers to your questions and learn how to prepare for an inspection using this FAQ.


Campaigns Overview and Focus

What is the focus of the campaigns?

The MLITSD is conducting two year-long campaigns to prevent injuries and illnesses that could arise from chemical exposure in the workplace.

Two campaigns are running simultaneously; both efforts to raise awareness and boost compliance on key occupational hygiene issues:

  • Worker exposures to chemical agents in the workplace

  • WHMIS training based on the amended Hazardous Products Regulations

The campaigns run from April 1, 2024 – March 31, 2025. Education and outreach will occur first, followed by workplace inspections, beginning July 2, and continuing until the end of March 2025.

Proactive inspections of workplaces will be conducted by MLITSD inspectors in any sector where workers work with or may be exposed in the course of their work to a hazardous product.

Throughout the campaigns the MLITSD, with the support of Workplace Safety & Prevention Services (WSPS), will provide education, outreach and awareness to assist businesses with their compliance efforts.

Why is this campaign important?

Occupational illnesses can be the result of acute and long-term exposures to hazardous chemical agents in the workplace. Controlling these exposures will help lower the risk of workers developing an occupational illness.

It is also important that workers understand the hazards associated with the products they work with so that they can take the necessary safety precautions to control their exposures.

This campaign aims to increase compliance with the Occupational Health and Safety Act (OHSA) and relevant Regulations.  

What are the goals of the Worker Exposures to Chemical Agents in the Workplace campaign:

  • Ensure compliance with R.R.O. 1990, Regulation 833: Control of Exposure to Biological or Chemical Agents in all workplaces where this regulation applies.

  • More specifically, MLITSD hygienists will ensure that workers are not exposed to hazardous substances exceeding the occupational exposure limits.

  • Assess worker exposures by identifying the hazards, observing work practices, evaluating effectiveness of controls.

  • Existing exposure data will be reviewed and/or a requirement for air sampling may be issued.

  • Contribute to the development of an exposure surveillance system.

What are the goals for WHMIS Training Based on the Amended Hazardous Products Regulations campaign:

  • Ensure compliance with R.R.O. 1990, Regulation 860, Workplace Hazardous Materials Information System (WHMIS) in all workplaces where this regulation applies.

  • More specifically, MLITSD hygienists will determine if retraining on WHMIS will be required depending on whether the hazardous products in the workplace have labels and safety data sheets that are compliant with the amended Hazardous Products Regulations (HPR).

What sectors are included?

These campaigns apply to all workplaces in any sector where workers may be exposed to chemical agents and/or where hazardous products are present.

I am a small business. Am I included in this campaign?

Yes.  The campaigns aim to provide awareness to workers who may be exposed to hazardous substances, regardless of the size of the business. 

I am an agriculture operation. Are we included?

Ontario Regulation 414/05 for Farming Operations specify where the Occupational Health and Safety Act and its regulations apply.  Although Ontario Regulations 833 and 860 do not apply to farming, certain aspects of an agriculture operation may be considered part of an industrial establishment in which case O. Regs 833 and 860 will apply and so will the hygiene campaigns.

An example could be a cannabis operation where parts of the facility will be considered farming while other parts will be considered industrial.  All regulations that apply to industrial establishments, including Regs 833 and 860, will be enforced in the industrial sections of the facility.

Will all businesses be inspected? 

No, not all businesses will be inspected.  

How will the MLITSD select which businesses to inspect? 

The MLITSD selects workplaces to be inspected based on many factors which may include:

  • knowledge of the business and its activities;

  • the risk of worker exposure to hazardous substances; and

  • prior history of non-compliance. 

In some cases, workplaces may also be selected simply because it has not been inspected previously.

Will the business be notified of a MLITSD inspector visit? 

Generally, no. The MLITSD inspector's visit will not be announced; however, there may be instances when the visit will be scheduled in advance depending on the specific circumstances of the situation.

What can I expect during an inspection?

  • An inspector has the right to enter and be granted access to all areas of the workplace.

  • When an inspector arrives at your workplace, they will introduce themselves, explain the reason for the visit, and ask a worker and management representative to accompany them during the inspection.

  • The Inspector may conduct an administrative review and a physical workplace inspection.

  • Inspectors will enforce the Occupational Health and Safety Act (OHSA) and its regulations based on the facts at the time of the inspection.

During an inspection, if an inspector finds a contravention under the OHSA:

  • An order may be issued.

  • The Inspector will explain the contravention and may refer the workplace to a health and safety association (e.g. Workplace Safety & Prevention Services) for compliance assistance. 

  • Inspectors issue stop-work orders where an immediate threat to worker health and safety has been observed, halting work completely until the issue is resolved.

  • A field visit report outlining the details of the visit, including orders issued, will be provided to the employer.

WHMIS Campaign Specific Questions

What are the triggers that would require WHMIS re-training?

  • If a Safety Data Sheet (SDS) has been updated by the supplier to make it compliant with the amended HPR

  • No proof of workplace specific training

  • Lack of worker knowledge on the hazards associated with the products they work with

What would a typical order look like? Does it require both workplace specific training, or just generic training? 

For lack of training or to update WHMIS training, an order may be issued under sections 6 or 7 of the WHMIS Regulation 860.  WHMIS training must always be site specific to ensure that workers are knowledgeable about the hazards of the products they work with.

What do we do if some suppliers have provided a Safety Data Sheet (SDS) as per the amended Hazardous Products Regulations (HPR), but others have not yet, so we have a bit of both?

Suppliers have until December 14, 2025, to revise their SDS and labels to make them compliant with the amended HPR.

Updated WHMIS training will need to be conducted as soon as the workplace starts receiving SDS and labels that are in line with the amended HPR. The updated WHMIS training can cover all the relevant changes that will affect the hazardous products found in the workplace, in anticipation of future changes in the SDS, so that additional retraining will not be required when all SDS have been revised to comply with the amended HPR.

Do all workers at my workplace require WHMIS training? 

As per Ontario Regulation 860, WHMIS training is required for workers who work with or who may be exposed in the course of their work to a hazardous product.

Do I have to do WHMIS training every year?

There is no specific requirement for annual WHMIS refresher training in the WHMIS Regulation, however this is a best practice. Training must be updated and implemented when work conditions change that may affect the health or safety of a worker, such as introducing new products, new information about safe handling, storage and use of chemicals.

See next question/answer for what is required annually.

What is the requirement for the joint health and safety committee (JHSC) or health and safety representative (HSR) to be involved in WHMIS training?

In the Occupational Health and Safety Act (OHSA) Section 42, the training must be developed and implemented by the employer in consultation with the JHSC or HSR. The employer must also review, in consultation with the JHSC or HSR the training provided to a worker and the worker’s familiarity at least annually.

The review must be held more frequently than annually if the employer, on the advice of the JHSC or HSR determines that such reviews are necessary, or there is a change in circumstances that may affect the health or safety of a worker.

What materials are not regulated by WHMIS? 

Section 4 of Ontario Regulation 860 outlines the application of the regulation and what products are not covered by WHMIS.

Do I require a Safety Data Sheet (SDS) for products I can purchase from stores (i.e. consumer products)? What are the requirements regarding consumer products at workplace? 

Consumer products are regulated by the Canada Consumer Product Safety Act. Refer to this Act for more details on the requirements related to consumer products.  WHMIS Regulation 860 exempts consumer products from the requirements of section 8 (supplier labels), section 14 (laboratory samples) and sections 17 and 18 (safety data sheets).  However, worker education will still be required.

If I manufacture materials, do I have to create Safety Data Sheets (SDSs)? How do I know what to include in a SDS? What data is required to be reviewed/drafted? 

Suppliers of hazardous products, which include manufacturers, are required by the federal Hazardous Products Act (HPA) to prepare and provide SDS and labels for their products.  The required information elements on the SDS and labels are prescribed in the Hazardous Products Regulations.

When is a supplier label required?

A supplier label is required for every hazardous product received from a supplier. The employer is required to ensure that the product is labelled and properly identified with a supplier label. If the supplier label becomes damaged or removed, the employer must replace the label with a new supplier label or a workplace label.   

When is a workplace label required?

An employer who produces hazardous materials that are not intended for sale is required to place a workplace label on the hazardous product or its container. Additionally, if an employer receives a hazardous product and the product is transferred to another container, the container then also requires a workplace label, unless

  • the product is used exclusively by the worker who made the transfer;

  • the transferred product is only used during the shift that the transfer occurred; and

  • the content of the container is clearly identified.

Or if all the hazardous product transferred to another container is required for immediate use.

Chemical Exposure Campaign Specific Questions

How do I know whether an agent has an occupational exposure level under Ontario Regulation 833?

What if I have never done air sampling? 

Consult a qualified individual, such as a Registered Occupational Hygienist (ROH) or a Certified Industrial Hygienist (CIH), to assist in conducting the air sampling. 

What if the air sampling I did was a few years ago? 

Best practice is to conduct air sampling annually or whenever there are changes in the work process, environment and practices which may affect worker exposures to hazardous substances.

Will the MLITSD do the air sampling for me? 

The MLITSD may issue a requirement for the employer to conduct air sampling at their expense.  Occasionally and depending on the circumstances, MLITSD may conduct the air sampling for the employer to determine compliance with the OHSA and its regulations.

Do I need to sample all my workers in air sampling?

Only workers who may be exposed to hazardous substances are usually included in the air sampling.  However, additional sampling is sometimes conducted depending on the situation (e.g. if the employer is determining the extent of airborne contamination outside of the immediate area where the contamination is generated). 

Businesses are advised to consult with a qualified individual to determine the best way to conduct air sampling.

What should I do if the results of the air sampling indicate that workers are exposed to hazardous substances above the occupational exposure limits? 

Follow the hierarchy of controls to control worker exposures. The hierarchy of controls is a series of methods to eliminate or reduce the exposure of hazards to workers.  It includes, in the order of the most effective method of control to the least effective:

  • Elimination

  • Substitution

  • Engineering controls

  • Administrative controls

  • Personal Protective Equipment (PPE)

You should always start from the most effective method of control – elimination – when determining controls to implement and its feasibility, then move to the next control method (substitution). Continue the process until you reach the least effective method – PPE – to ensure adequate controls have been identified to protect worker’s health and safety. A combination of controls may be necessary to reduce the risks associated with hazards to an acceptable level.  

As an employer, do I have to notify the MLITSD if I find out a worker has an occupational illness, and if so, how do I do this? 

Yes. According to Ontario Regulation 420 - Notices and Reports under Section 51 to 53.1 of the Act - Fatalities, Critical Injuries, Occupational Illnesses, and Other Incidents – if you as an employer become aware of a worker (current or former) who developed an occupational illness or filed a claim for an occupational illness with the Workplace Safety and Insurance Board (WSIB), you must submit a written notice. The notice must be submitted within 4 days of you becoming aware, and it is to be submitted to MLITSD, the joint health and safety committee (JHSC) or health and safety representative, and the union (if applicable). You may use the form provided by the MLITSD, available on their website, to complete the written notice and submit the form electronically.  

Working with WSPS

Am I required to work with WSPS? 

WSPS' health and safety consultants are located across Ontario and are available to support businesses of all sizes understand their obligations under the Occupational Health and Safety Act (OHSA), as well as connect them with resources to get started. Employers are not required to engage with WSPS and can rely on support from other available resources. 

Is there a cost for WSPS consulting services?

Advice and guidance are always free from WSPS as the employer’s paid Workplace Safety and Insurance Board (WSIB) premiums. If you transition from free to fee-for-service support, your WSPS consultant will bring that to your attention before any work begins. You will never receive a surprise bill from WSPS.

What type of support can I expect from WSPS?

WSPS has created several free resources to assist with the campaign. These resources will help you recognize and identify areas in which you are doing a great job of preventing injuries and areas where you may need more help. 

Every business has unique challenges and constraints based on size and available resources. WSPS is committed to supporting all businesses, ensuring responsibilities under the Occupational Health and Safety Act (OHSA) are understood and implemented using a strategic and integrated approach. We leverage our experience and existing relationships with our system partners and engage research institutions to get you the information your business needs to implement sustainable solutions that will impact employee well-being and overall business performance.

Many consultants sit on CSA and ISO standard committees to ensure Ontario workplaces get the latest information to prevent injuries.

For more information and updates, visit, contact your local account manager, or contact WSPS (1-877-494-9777).


WSPS Resources

  • Occupational hygiene supports – both free and fee-for-service – can be found on

  • Employers are invited to engage with a local WSPS account manager or consultant, who will offer assistance in supporting the initiative/campaigns. You can connect with us via our website or call our Customer Care team (1-877-494-9777) 

  • Occupational Hygiene Services

o   Air Exposure Monitoring

o  Designate Substance Assessment

o  Designated Substance Control Program development

o   Quantitative

o   Qualitative

o   Chemical Management Program

o   Chemical Inventory Assessments

o   Creation of Chemical Specific Training documents

o   WHMIS/Chemical Management Building Block

o   WHMIS for Workers - Online Instructor-Led (3.5 hours)

o   WHMIS – In Person (3.5 hours)

o   E course (1 hour)

o   Custom Workplace Specific WHMIS training

o   WHMIS for Agriculture – In Person (2 hours)

Be sure to visit frequently to discover new resources and information about the campaign throughout the year. 

MLITSD Resources

Other Resources

Contact Information

If you have additional questions about this campaign, please get in touch with WSPS (1-877-494-9777). 

You can reach the MLITSD Health and Safety Contact Centre as follows: