Safety Data Sheets (SDS)

A Safety Data Sheet, or SDS, is a comprehensive technical document that provides detailed information about a hazardous product. While labels provide essential information at a glance, the SDS contains in-depth technical and safety information that workers, supervisors, and emergency responders need to handle, store, and respond to hazardous products safely. Every hazardous product covered by WHMIS must have an SDS.

Under WHMIS 1988, these documents were called Material Safety Data Sheets (MSDS). WHMIS 2015 changed the name to Safety Data Sheets and, more importantly, standardized the format. All SDSs must now follow a consistent 16-section format in a specific order. This standardization makes it much easier to find information because the same type of information always appears in the same section, regardless of the product or supplier.

SDSs serve multiple audiences. Workers use SDSs to understand the hazards of products they work with and to learn safe handling procedures. Supervisors and managers use SDSs to develop safe work procedures, select appropriate personal protective equipment, and plan for emergencies. Health and safety professionals use SDSs to conduct workplace assessments and exposure monitoring. Emergency responders use SDSs when responding to spills, fires, or other incidents involving hazardous products.

Employers are legally required to ensure that an SDS is readily accessible to workers for every hazardous product in the workplace. "Readily accessible" means workers can access the SDS quickly during their work shift. Many employers maintain both paper and electronic SDS collections, though if SDSs are kept electronically, workers must have access to the necessary equipment to view them, and a backup system must be available if electronic systems fail.

Section 1, Identification, provides basic product and supplier information. This section includes the product identifier (which must match the label), other means of identification (such as trade names or synonyms), recommended use of the chemical and restrictions on use, and details of the supplier including name, address, and emergency phone number. This section also includes the emergency telephone number, which is critical in case of incidents.

Section 2, Hazard Identification, contains the same information that appears on the label. This includes the classification of the hazardous product, the signal word (Danger or Warning), hazard pictograms, hazard statements, and precautionary statements. This section may also include other hazards not classified under WHMIS but which the supplier chooses to communicate, such as combustible dust hazards. Having label information in the SDS allows workers to reference it even if they cannot read the label on the container.

Section 3, Composition/Information on Ingredients, identifies the chemical ingredients in the product. For pure substances, this section provides the chemical name, common name and synonyms, CAS number (a unique identifier for chemicals), and impurities and stabilizing additives that are themselves hazardous. For mixtures, this section lists hazardous ingredients above certain concentration thresholds. Note that some chemical identity information may be protected as confidential business information, but health and safety information must still be disclosed.

Section 4, First-Aid Measures, describes immediate care that should be given to a person exposed to the product. This section is organized by exposure route (inhalation, skin contact, eye contact, ingestion) and provides instructions for each. It also describes the most important symptoms and effects (both acute and delayed) and indicates whether immediate medical attention is required. While this information is valuable for initial response, remember that serious exposures require professional medical care, and this section should not be considered a substitute for medical advice.

Section 5, Fire-Fighting Measures, provides information for firefighters and emergency responders. It describes suitable extinguishing media (what types of fire extinguishers or suppression systems work for this product) and unsuitable extinguishing media (what should not be used). It identifies specific hazards arising from the chemical, such as toxic combustion products, and recommends special protective equipment and precautions for firefighters. This information is crucial during fire emergencies.

Section 6, Accidental Release Measures, describes appropriate response procedures for spills, leaks, or releases. It covers personal precautions, protective equipment, and emergency procedures, including whether to evacuate the area. It explains environmental precautions to prevent the release from spreading to drains or waterways. It also provides methods and materials for containment and cleanup, specifying what materials to use to absorb or contain the spill and how to dispose of contaminated cleanup materials.

Section 7, Handling and Storage, provides guidance for safe handling practices to minimize risks. This includes precautions for safe handling such as hygiene measures and technical measures like ventilation requirements. It describes conditions for safe storage, including any incompatibilities with other materials. This section tells you what materials should not be stored near each other because they could react dangerously if mixed. Following the guidance in this section helps prevent incidents.

Section 8, Exposure Controls/Personal Protection, is one of the most practically important sections for workers. It lists occupational exposure limits (such as Threshold Limit Values or Permissible Exposure Limits) that define safe exposure levels. It describes appropriate engineering controls such as ventilation systems or enclosed processes. Most importantly for workers, it specifies required personal protective equipment for eyes, face, skin, hands, respiratory system, and other body areas. This section tells you exactly what PPE you should wear when working with the product and may specify particular types or materials of PPE that provide adequate protection.

Section 9, Physical and Chemical Properties, lists characteristics such as appearance, odor, pH, melting point, boiling point, flash point, flammability limits, vapor pressure, vapor density, relative density, solubility, and other properties. While highly technical, these properties help understand how the product behaves and what hazards it presents. Section 10, Stability and Reactivity, describes the chemical stability of the product, the possibility of hazardous reactions, conditions to avoid (such as heat or shock), incompatible materials that could cause dangerous reactions, and hazardous decomposition products that might form.

Section 11, Toxicological Information, provides detailed scientific information about health effects. This includes likely routes of exposure, symptoms related to physical, chemical, and toxicological characteristics, and delayed and immediate effects as well as chronic effects from short- and long-term exposure. It includes numerical measures of toxicity such as LD50 and LC50 values. This section is often technical but provides the scientific basis for the hazard classifications and health warnings.

Section 12, Ecological Information, addresses environmental effects including ecotoxicity, persistence and degradability, bioaccumulative potential, and mobility in soil. Section 13, Disposal Considerations, provides guidance on safe disposal methods, though it typically refers users to local regulations since disposal requirements vary by location. Section 14, Transport Information, covers shipping classifications and requirements under transportation of dangerous goods regulations. Section 15, Regulatory Information, cites safety, health, and environmental regulations specific to the product. Section 16, Other Information, includes the date of preparation or last revision, any changes since the last version, and other information such as key references.

To use an SDS effectively, first ensure you are looking at the correct SDS for your product by checking that the product identifier matches. Then consult the specific sections relevant to your needs. Section 2 gives you a quick overview of hazards. Section 8 tells you what protective equipment to use. Sections 4 and 6 are critical for emergency response. Review the SDS before working with a new product, and refer back to it whenever you have questions. Employers must ensure SDSs are current; suppliers must update SDSs within 90 days of receiving new hazard information, and employers must replace older SDSs with updated versions. Remember that SDSs are technical documents, and if you do not understand something in an SDS, ask your supervisor or health and safety representative for clarification.