WHMIS - Authoring Safety Data Sheets (SDSs)

Safety Data Sheets (SDSs) are summary documents that provide information about a product's hazards and advice about safety precautions. They are usually written by the product manufacturer or supplier and must be provided by the suppliers of the hazardous products at the time of sale. In some circumstances, an employer may be required to prepare an SDS (e.g., when the product is produced and used exclusively in that workplace).

This document discusses who is responsible for creating the WHMIS-compliant SDS and the steps for authoring one. For general requirements, such as when an SDS is required in a workplace, how to obtain one, and other information, see our OSH Answer WHMIS – Safety Data Sheet (SDS).

Requirements for WHMIS-compliant SDSs are specified in the following pieces of legislation:

• Suppliers: The federal supplier WHMIS legislation consists of the Hazardous Products Act (HPA) and the Hazardous Products Regulations (HPR) issued under the HPA. This legislation applies to suppliers (i.e., manufacturers, importers, distributors) who sell hazardous products that are NOT exempt under the HPA. The HPR specifies the classification criteria for hazardous products, the required information that must be provided in SDSs, and the SDS format requirements
• Employers: The WHMIS legislation issued by local jurisdictions applies to employers and workplaces (i.e., provincial, territorial, and federal). For example: 
  • Ontario: Regulation 860: Workplace Hazardous Materials Information System (WHMIS) issued under the Occupational Health and Safety Act 
  • British Columbia: Occupational Health and Safety Regulation, Part 5: Chemical Agents and Biological Agents, issued under the Workers' Compensation Act
  • Quebec: Hazardous Products Information Regulation, issued under the Act respecting Occupational Health and Safety 

No. Only products sold by a supplier or produced at an employer’s workplace that meet the following criteria will require a WHMIS-compliant SDS:

• The product or biohazardous infectious material meets the criteria in one or more of the WHMIS classes listed in the federal Hazardous Products Act (HPA) or Hazardous Products Regulation (HPR)
• The substance or product is listed in Schedule 4 of the HPR

The WHMIS regulations exempt suppliers and employers from preparing WHMIS-compliant SDSs for specific products because they are already regulated by other legislation. These exempt products are either fully or partially exempt from the jurisdictional WHMIS legislation. 

Many suppliers prepare SDSs voluntarily as a value-added service to their customers, such as consumer products that are used in the workplace. 

In addition, substance-specific legislation or regulatory agencies may recommend WHMIS-style SDSs be prepared for products not covered under the WHMIS legislation. For example, the Pesticide Management Regulatory Agency (PMRA) encourages the authoring of SDSs for pesticide registrants.

WHMIS-compliant SDSs must be provided by:

• the supplier (that is, manufacturers, importers, distributors) of WHMIS hazardous products or substances, or
• the employer for on-site produced WHMIS hazardous products or substances

While there are many similarities, a Globally Harmonized System of Classification and Labelling of Chemicals (GHS)-compliant SDS may not comply with Canada’s federal WHMIS legislation. 

The SDS provided to Canadian importers or workplaces must contain the required information. While a WHMIS-compliant SDS can contain additional information, such as other GHS hazard classes that were not adopted by Canada, any additional information must not conflict with the required information.  

If the SDS is not WHMIS-compliant, section 14 of the HPA requires Canadian suppliers who import a hazardous product intended for use, handling, or storage in a workplace in Canada to obtain or prepare, on or before the importation, an SDS for the hazardous product that meets the requirements of the HPR. 

No. While the federal and jurisdictional WHMIS legislation do not specify qualifications for SDS authors or classifiers, other health and safety workplace legislation has a general duty clause that requires the employer or supplier to exercise due diligence in selecting a competent person for this task.  

Generally speaking, the competent person must be able to classify the hazardous product as part of their process when preparing an SDS. 

For due diligence reasons, the supplier or employer must select a competent SDS author in case of an incident, insurance requirements, or a lawsuit from a customer. The SDS author, who also classifies hazardous products, needs to be knowledgeable about the following subjects: 

• Legal requirements
• Chemistry for chemical substances or products
• Microbiology or biochemistry for biological infectious materials
• Toxicology, and 
• Industrial hygiene

Training in SDS authoring is offered by the American Industrial Hygiene Association (AIHA®) and other organizations. 

To assist suppliers with authoring WHMIS-compliant supplier SDSs, Health Canada has issued the following guides:

• Guidance on the WHMIS supplier requirements (includes information on USA variances from Canada)
• Technical Decision Trees (health hazard classes) 

Other resources that may be helpful are: 

• Classifications for some chemicals are provided by Quebec’s Commission des normes, de l'équité, de la santé et de la sécurité du travail (CNESST) 
• Safety Data Sheet Compliance Tool (CCOHS and Health Canada)
• WHMIS – HCS 2024 Variances (Variances between Canada and USA)
• Globally Harmonized System of Classification and Labelling of Chemicals (GHS) (GHS purple manual) 7th revised edition 
• Globally Harmonized System of Classification and Labelling of Chemicals (GHS) (GHS purple manual) 8th revised edition   
• European (EU) ECHA Guidance documents for their GHS-based legislation 

*We have mentioned these organizations as a means of providing a potentially useful referral. You should contact the organization(s) directly for more information about their services. Please note that mention of these organizations does not represent a recommendation or endorsement by CCOHS of these organizations over others of which you may be aware.

It will depend. The SDS author must determine if any changes in the legislation impact the WHMIS classification of the hazardous substance or product. For example, if a new hazard class (e.g., chemicals under pressure) is adopted or the classification criteria are amended for a hazard class, the SDS author must determine if the WHMIS classification will change for their hazardous substances or products. When a hazardous substance needs to be reclassified due to new amendments in the legislation, the SDS will need to be reviewed for possible revision of the content based on the new WHMIS classification.

It depends. When a WHMIS “hazardous product” is purchased from a supplier as a concentrate that will be diluted at a workplace, this product is considered to be “potentially an employer-produced hazardous product.” The provincial/territorial/federal WHMIS Regulations require the employer to classify “employer-produced products” according to the classification criteria in the HPR of the federal WHMIS legislation. 

So, if a competent person (e.g., chemist, toxicologist, etc.) determines that the diluted “employer-produced product” meets the classification criteria for one or more of the hazard classes in the HPR of the federal WHMIS legislation, the “employer-produced product” will be deemed to be an “employer-produced hazardous product.” In such a case, a WHMIS-compliant SDS must be prepared. 

It depends. Generally, concentrated solutions are expected to be more hazardous than diluted ones. So, if the employer implements the same control measures for diluted solutions as for concentrated ones, the control measures will be sufficient to protect. However, the control measures may be overprotective or unnecessary, especially if the substance is diluted sufficiently and does not meet the WHMIS classification criteria.

However, caution must be exercised as HPA prohibits suppliers from selling or importing hazardous substances if the SDS contains information that is false, misleading, or likely to create an erroneous impression. 

Thus, it is recommended that the SDS author classify the diluted solutions of a concentrated product and prepare SDSs that provide appropriate control measures for the hazards. See the table below for WHMIS classifications for different solution strengths of ammonia.  Note that as the ammonia solutions become more concentrated (higher percentage of ammonia), there are additional hazards. 

Table 1: Sample Chemical Solutions and Hazards

Please note that this classification was retrieved from the CNESST site on September 2, 2025 and was established by CNESST personnel to the best of their knowledge based on data obtained from scientific literature and it incorporates the criteria contained in the Hazardous Products Regulations (SOR/2015-17). It does not replace the supplier’s classification which can be found on its Safety Data Sheet.

Yes, if the product or substance is determined to meet one or more of the WHMIS classification criteria.

If you consider any information in the SDS proprietary, you must submit a confidential claim with Health Canada under the Hazardous Materials Information Review Act. For additional information, see the OSH Answer Fact Sheet WHMIS - Confidential Business Information (CBI).

There are many commercial SDS authoring software programs available. An in-house SDS authoring specialist is required to validate the data, analyze the data, and determine the toxicity and safety hazards based on the ingredient’s properties. Most software applications are designed to streamline the time the SDS author specialist takes to generate the SDS, especially when there are variations in ingredient concentrations or formulation changes. 

Please note that CCOHS cannot provide specific recommendations for consultants or products.  Below are resources that can be used to select consulting firms that author SDSs.

• CCOHS: Selecting and Hiring and Health and Safety Consultant
• Alberta: Tips on Selecting an OHS Consultant - OHS information for employers
• Manitoba: Hiring an Occupational Health and Safety Consultant

*We have mentioned these organizations or certifications as a means of providing a potentially useful referral. You should contact the organization(s) directly for more information about their services. Please note that mention of these organizations does not represent a recommendation or endorsement by CCOHS of these organizations over others of which you may be aware.