What are the differences between the NIOSH list, the Hazardous Products Act and WHMIS hazard categories? Which should we follow to complete our annual risk assessments?

The National Institute for Occupational Safety and Health (NIOSH) is a recognized occupational health and safety agency, and part of the U.S. Centers for Disease Control and Prevention. The NIOSH List of Hazardous Drugs in Healthcare Settings, 2024 places hazardous drugs into tables based on specific criteria.

Any drug or active pharmaceutical ingredient (API) that is not included on the NIOSH list did not meet their specific criteria for a hazardous drug. However, it is important to read the NIOSH document in its entirety (i.e., do not only refer to the list of drugs in each table). The actual risk to personnel depends on how the drug is handled and what risk mitigation measures are in place.*

The Hazardous Products Act (HPA) is the legislation that that enforces safety measures. It establishes hazard classifications and mandates that any supplier who sells or imports a hazardous product intended for use, handling or storage must provide cautionary labelling requirements and a safety data sheet (SDS).

The Workplace Hazardous Materials Information System (WHMIS) is Canada’s hazard communication standard to support the safe use of hazardous materials in the workplace. It includes products used in various workplaces – a far wider group of chemicals than NIOSH. These are categorized as either a physical hazard or a health hazard (see Schedule 2 of the HPA). It also identifies products that can be very irritating to the respiratory tract, skin or mucous membranes, which is important for determining the level of requirements.

Both NIOSH and WHMIS provide information on toxicities of drugs. The WHMIS also includes information on other workplace products. Both references should be consulted in the risk assessment process, as described in Section 4 of the guidance document and illustrated in the decision algorithm.

Safety data sheets and other applicable references should be reviewed, accessible and easily retrievable for every single ingredient in a compounded preparation (see next question).

Risk assessments should be done for each compounded preparation. They should be made available to all staff so they can review them and understand the risks.

*The NIOSH List is designed to help employers to identify which drugs handled by employees are considered by NIOSH to be hazardous drugs. Because new drugs and new formulations are continuously brought to market between NIOSH’s periodic updates, hazardous drug evaluation should be a continual process. Employers should establish their own procedures to identify and evaluate new drugs as they enter their workplace and, when appropriate, reassess their presence on hazardous drug lists as toxicological data become available to support re-categorization. (Source)

Refer to Sections 4.3 and 8.3 of the NAPRA Guidance Document for Pharmacy Compounding of Non-Sterile Preparations. Note that where the guidance document uses the language of “should,” it may be acceptable to meet the required standard using other technologies, techniques, materials and procedures than those suggested only if they have been proven to be equivalent or superior to those described in the guidance document.