A clear liquid in a beaker could be water, or it could be an acid that burns skin, or alcohol that catches fire from a spark. You cannot tell by looking. That is why hazardous products used at work in Canada, including in school labs, come with standard symbols and information that tell you what it can do and how to handle it. Knowing how to read them, and following a few safe habits, prevents most lab injuries. Safety is a skill, just like measuring or graphing, and you will use it in every investigation.
What WHMIS is
WHMIS stands for the Workplace Hazardous Materials Information System, Canada's national system for giving information about hazardous products used at work. In 2015 it was updated to match the Globally Harmonized System (GHS), so Canada now uses the same pictograms and label style as many other countries. WHMIS has three main parts: labels on containers, Safety Data Sheets (SDS) with detailed information, and education and training so that workers know how to use the first two. Each hazard pictogram is a black symbol inside a red diamond-shaped border, except one (biohazardous infectious materials), which has a round black border.
| Pictogram | What the hazard is | Example |
|---|---|---|
| Flame | Flammable: catches fire easily (also some products that heat up or give off flammable gas) | Ethanol, acetone (nail polish remover) |
| Flame over circle | Oxidizer: gives off oxygen, so it makes other materials burn more fiercely | Concentrated hydrogen peroxide, potassium nitrate |
| Exploding bomb | Explosive or self-reactive: can explode or react violently on its own | Some organic peroxides |
| Gas cylinder | Gas under pressure: can burst or explode if heated or damaged | Compressed oxygen or propane cylinder |
| Corrosion | Corrosive: burns skin and eyes, damages metals | Concentrated hydrochloric acid, sodium hydroxide |
| Skull and crossbones | Acute toxicity: can cause serious poisoning or death after one short exposure, even in small amounts | Methanol |
| Exclamation mark | Less serious health effects: skin or eye irritation, allergic skin reactions, drowsiness, or harm if swallowed | Many dilute lab solutions and cleaners |
| Health hazard | Serious long-term health effects: cancer, damage to organs, harm to an unborn child, or asthma-like reactions | Formaldehyde, some solvents |
| Biohazardous infectious materials (round border) | Living organisms or toxins that can cause disease | Cultures of disease-causing bacteria, blood samples |
| Environment (GHS; not required in WHMIS) | Harmful to fish and other aquatic life | Some pesticides |
Supplier labels and workplace labels
- Product identifier (the name of the product)
- Initial supplier identifier (company name and contact information)
- Hazard pictogram(s)
- Signal word: "Danger" for more severe hazards or "Warning" for less severe ones
- Hazard statements (what the hazard is) and precautionary statements (how to stay safe, first aid)
- In both English and French
- Needed when a product is moved into another container that will be kept (not just used right away), made on site, or the supplier label is damaged
- Product identifier
- Safe handling information (may include pictograms)
- A statement that a Safety Data Sheet is available
- Example: the label on a wash bottle of dilute acid filled from a large stock bottle
Safety Data Sheets
A Safety Data Sheet (SDS) is a document from the supplier with much more detail than a label can hold. It is organized into 16 sections, always in the same order, including: identification of the product, the hazards, what is in it, first-aid measures, what to do in a fire, how to clean up a spill, safe handling and storage, exposure controls and personal protection (which PPE to wear), physical and chemical properties, and how reactive it is. An SDS must be available for every hazardous product in a workplace. If someone is injured, the SDS tells first aiders and doctors exactly what the person was exposed to.
Personal protective equipment and safe habits
- Wear PPE. Safety goggles whenever chemicals, heat or glass are in use; a lab apron or coat; gloves when the label or SDS calls for them. Wear closed-toe shoes and tie back long hair and loose clothing.
- Read before you start. Read the whole procedure and every label first. If you are unsure what a product is or how to handle it, ask before you begin.
- Know your safety equipment. Find the eyewash station, fire extinguisher, fire blanket, first-aid kit and exits before the lab starts.
- No food or drink in the lab, and never taste anything. To smell a substance, waft the vapour toward your nose with your hand instead of sniffing directly.
- Handle heat carefully. Point a heated test tube away from yourself and others, and use tongs or heat-resistant gloves for hot glassware (hot glass looks the same as cold glass).
- When diluting acid, add acid to water, slowly, never water to acid, which can make the mixture boil and spatter.
- Report every accident, spill or broken glass right away, even if it seems small, and clean up only as directed. Dispose of chemicals as instructed, not down the sink by default, and never return unused chemicals to the stock bottle.