Why hazard communication matters

Almost every workplace uses hazardous products. Cleaning chemicals in a school, solvents in a print shop, fuels at a gas station, compressed gases in a hospital, battery acid in a warehouse, refrigerants in a data centre and paints on a construction site can all cause fires, burns, poisoning, breathing problems or long-term illness if they are handled without the right information. The Workplace Hazardous Materials Information System, known as WHMIS, is Canada's national system for making sure that the people who use hazardous products know what the hazards are and how to protect themselves. This course explains how WHMIS works: how products are classified, what labels and safety data sheets tell you, how to handle, store and respond to hazardous products safely, and what employers, suppliers and workers must each do.

About this course

This is an awareness-level course. It gives you a solid general understanding of WHMIS and of working safely with hazardous products, and it can form part of the general education that employers must provide. It does not replace the workplace-specific training that your employer must give you on the actual products, procedures and emergency arrangements at your workplace, and it does not replace any certified training required for particular jobs, such as transportation of dangerous goods, respiratory protection or first aid. Requirements vary between federal, provincial and territorial jurisdictions, so always follow the rules and procedures that apply where you work, and ask your supervisor or joint health and safety committee if you are unsure.

How hazardous products harm people

Hazardous products can cause harm in two broad ways. Physical hazards come from the properties of the product itself: it may catch fire, explode, react violently with other materials, release gas under pressure, or corrode metal. Health hazards come from the product's effects on the body: it may poison you if swallowed, inhaled or absorbed through the skin; burn your skin or eyes; trigger allergies or asthma; damage organs such as the liver, lungs or nervous system; or cause cancer, genetic damage or harm to an unborn child after long or repeated exposure. Some effects are immediate and obvious, such as a chemical burn. Others are delayed or hidden, appearing months or years later, such as occupational asthma or cancer. Because many hazardous products look, smell and feel like ordinary liquids, powders or gases, you cannot rely on your senses to tell whether something is dangerous. That is why written hazard information on labels and safety data sheets is essential.

The right to know

Hazard communication rests on a simple principle: people have a right to know about the hazards they work with. This right developed through the twentieth century as occupational diseases became better understood. Workers in the past often handled chemicals labelled only with trade names, with no information about what was inside or how dangerous it was. Many suffered poisoning, cancer and other diseases that could have been prevented. Labour unions, health researchers and safety advocates campaigned for laws requiring that chemical hazards be disclosed and that workers be trained.

In Canada, governments, employers and labour developed WHMIS together, and it came into force across the country on October 31, 1988. It was one of the first national hazard communication systems in the world. Along with the right to participate in health and safety and the right to refuse unsafe work, the right to know is one of the three basic rights that occupational health and safety laws in every Canadian jurisdiction give workers. In 2015, WHMIS was updated to align with the international Globally Harmonized System, becoming WHMIS 2015, and it has since been amended to follow later GHS revisions.

The Globally Harmonized System

Before the 2010s, countries classified and labelled chemicals in different ways. A product could be labelled "toxic" in one country and "harmful" in another, with different symbols, criteria and safety data sheet formats. This confused workers, made trade difficult and meant that hazards were communicated inconsistently. The United Nations developed the Globally Harmonized System of Classification and Labelling of Chemicals, known as the GHS, first published in 2003 and revised every two years since. The GHS provides common criteria for classifying chemical hazards, standard label elements such as pictograms, signal words and hazard statements, and a standard 16-section format for safety data sheets. The GHS is not a law itself; each country chooses which parts to adopt, through its own legislation. Canada and the United States have both adopted the GHS for workplace chemicals, which is why WHMIS and HazCom now look very similar, though there are some differences that this course points out. Lesson 2 explains the GHS and the legal framework in more detail.

The three main elements

WHMIS rests on three main elements:

• Labels on containers of hazardous products, which alert you to the main hazards and the basic precautions.
• Safety data sheets (SDSs), which give detailed information about the product's hazards, safe handling, storage, emergency measures, properties and regulatory status.
• Worker education and training, which helps you understand the labels and SDSs and know the specific procedures for working safely with the products at your workplace.

These elements work together. A label gives a quick warning at the point of use; the SDS gives the full picture; training makes sure people can understand and act on the information. If any element is missing, hazard communication fails: a perfectly labelled drum is little use if workers do not know what the pictograms mean, and a complete SDS filed away where no one can find it protects no one.

Who is involved

WHMIS gives different groups different duties. Suppliers, meaning anyone who sells or imports hazardous products in Canada for use in workplaces, must classify their products, prepare supplier labels and SDSs that meet the Hazardous Products Regulations, and provide them to purchasers. Employers must make sure hazardous products in the workplace are properly labelled, that current SDSs are available to workers, that workers are educated and trained, and that products are handled, stored and controlled safely. Workers must take part in education and training, follow safe work procedures, use the controls and protective equipment provided, and report hazards such as damaged or missing labels. Lesson 12 discusses these duties in detail.

What hazard communication covers and does not cover

WHMIS applies to hazardous products, defined in the Hazardous Products Act as products, mixtures, materials and substances that meet the criteria for one or more hazard classes. Some products are covered by other laws and are excluded from WHMIS supplier label and SDS requirements, including explosives covered by the Explosives Act, cosmetics, drugs and foods regulated under the Food and Drugs Act, pest control products under the Pest Control Products Act, radioactive nuclear substances, consumer products sold at retail, wood and products made of wood, tobacco, manufactured articles and hazardous waste. Even when a product is excluded, employers still have general duties under occupational health and safety law to inform workers about its hazards and protect them. For example, a household cleaner bought at a store and used at work may not have a WHMIS label, but the employer must still make sure workers know how to use it safely.

Hazard communication and other safety rules

WHMIS is one of several systems for communicating chemical hazards. Transportation of dangerous goods (TDG) rules, under federal and provincial TDG legislation, govern the labels, placards and documents used when hazardous products are shipped by road, rail, air or water; TDG labels and placards look different from WHMIS labels and serve emergency responders during transport. Consumer chemical products sold in stores carry labels under the Consumer Chemicals and Containers Regulations, 2001. Pesticides carry labels approved by Health Canada's Pest Management Regulatory Agency. Workplace exposure limits, ventilation, respirator programs and confined space rules are set by occupational health and safety regulations. A product may carry several types of labels during its life: a TDG label on the shipping box, a WHMIS supplier label on the container, and a workplace label on a smaller container filled at work.

Why it matters: the cost of failure

Failures of hazard communication cause serious injuries and deaths every year. Common scenarios include workers mixing bleach with an ammonia-based or acidic cleaner, producing toxic gases; using a flammable solvent near an ignition source because the container had no label; entering a tank or pit without knowing that a previous product could release toxic vapour; transferring a chemical into an unlabelled drink bottle that someone later drinks from; and developing occupational asthma after months of exposure to a sensitizer that no one recognized as hazardous. Each of these could have been prevented by a clear label, an accessible SDS and training. Hazard communication violations are consistently among the most frequently cited workplace safety violations, showing how often the basics are missed.

How this course is organized

Lesson 2 explains the GHS and the legal framework. Lessons 3 and 4 explain how physical and health hazards are classified. Lesson 5 covers pictograms, signal words and hazard and precautionary statements. Lessons 6 and 7 cover supplier and workplace labels. Lessons 8 and 9 cover safety data sheets and how to read them. Lesson 10 covers exposure, exposure limits and controls, Lesson 11 safe handling, storage, spills and emergencies, and Lesson 12 roles, training, programs and the capstone.

Key words to know from the start

A few terms recur throughout the course. A hazard is anything with the potential to cause harm; risk is the likelihood and severity of harm in a particular situation, which depends on exposure. Exposure means contact with a hazardous product, whether by breathing it, touching it, swallowing it or having it injected. Controls are measures that reduce exposure or the chance of an incident, from eliminating a product to wearing gloves. Keeping these ideas separate helps you understand why a highly hazardous product can sometimes be used safely, and why a seemingly mild one can cause harm when exposure is high.

Throughout the course, look for the products you actually use at work and compare their labels and SDSs with the examples. Applying each lesson to real products is the best way to turn awareness into safe habits.