This is the reference page — how to read a label, where the information lives, and the handful of practices that prevent almost every accident in a school lab. The agreement you sign before your first investigation is Safety in the Lab; this page is what that agreement is built on.
You will use it more than you used the Grade 10 version, because this year you are handling a wider range of substances, in larger amounts, in procedures you designed yourself.
WHMIS in one paragraph
WHMIS — the Workplace Hazardous Materials Information System — is Canada’s law-backed system for telling anyone who handles a hazardous product what it can do to them and what to do about it. It is harmonised with the international system used in most of the world, so a label printed in Germany and one printed in Ontario carry the same symbols. It has three parts: labels on containers, a safety data sheet for each product, and training for the people using it. That third part is this page, and the class it comes from.
The nine pictograms, by what they are warning you about
The picture is a summary, not the instruction. It tells you what kind of harm is possible so you know which precautions to read first.
| Pictogram | What is drawn | What it signals |
|---|---|---|
| Flame | A flame | Flammable and combustible materials, including ones that ignite in air, heat themselves, or release flammable gas on contact with water |
| Flame over circle | A flame above a circle | Oxidizing materials — they feed a fire, and can start one in things that would not otherwise burn |
| Gas cylinder | A gas cylinder | Gases under pressure, including compressed, liquefied, refrigerated, and dissolved gases |
| Corrosion | Liquid dropping onto a hand and onto a surface | Corrosive to skin and to eyes; some are corrosive to metals as well |
| Exploding bomb | A bursting sphere | Explosives, and the self-reactive materials and organic peroxides that can detonate |
| Skull and crossbones | A skull above crossed bones | Acute toxicity — serious harm or death from a small amount, quickly |
| Health hazard | A starburst inside a human torso | Serious, often delayed effects — cancer, reproductive and genetic harm, respiratory sensitisation, organ damage, aspiration hazard |
| Exclamation mark | An exclamation mark | Less severe effects — skin and eye irritation, skin sensitisation, drowsiness or dizziness |
| Biohazardous infectious materials | Three crescents arranged around a central circle | Micro-organisms and their toxins that cause disease in people or animals |
You will also meet a dead fish and dead tree symbol on many labels, marking hazards to the aquatic environment. It comes from the same international system, though it is not one that WHMIS itself requires in Canada. Treat it as real information: it is telling you the product must not go down the sink.
Two symbols people mix up
The skull and crossbones means a small amount can hurt you within minutes. The health hazard starburst means the damage may take years to appear and may never be traceable to today. The second one looks less alarming and is often the more serious of the two, because nothing about handling it will feel dangerous at the time — which is precisely why the label has to tell you.
Reading a label
A supplier label — printed by whoever manufactured or imported the product — carries the product identifier, the supplier’s name and contact information, the pictograms, a signal word, hazard statements saying what the product does, and precautionary statements saying what to do about it.
The signal word is doing real work and is easy to skim past. Danger marks the more severe hazards; Warning marks the less severe. Two bottles with the same pictogram and different signal words are not equally dangerous, and the word is the only place that difference appears on the front of the container.
When a chemical is decanted into a smaller container for a class, it needs a workplace label: the product name exactly as it appears on the safety data sheet, the precautions for handling it, and a pointer to that sheet. Anything else is an unlabelled container.
An unlabelled beaker is not a puzzle to solve by smelling it or testing it. It comes to me, and it gets disposed of. This costs the school nothing and has never once been the wrong call.
The safety data sheet
Every hazardous product has an SDS, written in a standard order of sixteen sections, so the same information sits in the same place on any product from any supplier. You will never read all sixteen. These are the ones you will actually open:
| Section | Question it answers |
|---|---|
| 2 — Hazard identification | What can this do to me? |
| 4 — First-aid measures | What do we do in the first two minutes? |
| 6 — Accidental release measures | It is on the bench. Now what? |
| 7 — Handling and storage | How is it kept, and what must it not sit beside? |
| 8 — Exposure controls and personal protection | What do I need to wear? |
| 10 — Stability and reactivity | What must it never be mixed with? |
Sections 6 and 10 are the Grade 11 additions, and section 10 is the one worth learning to use. It lists incompatible materials — the things that turn a manageable substance into an unmanageable one. This is why acids and bases are not stored on the same shelf, why oxidising agents are kept away from anything flammable, and why the answer to “can I just put these two in the same waste beaker” is always check first.
Sheets for everything in this room are kept where I will show you on the first lab day. Read section 4 before the investigation, not during the accident.
The practices that prevent most of it
- Eye protection goes on when you enter and comes off when the last person has cleaned up — not when your own work is done. Somebody else’s splash is still your eyes. Tell me if you wear contact lenses, so we can make sure your eye protection is right for them.
- Long hair tied back, loose sleeves secured, closed-toe shoes. Spills and broken glass go down.
- Never pipette by mouth. Ever, with anything, including water. Use a bulb or a pump — Measuring Well shows how.
- Add acid to water, never water to acid. Diluting a concentrated acid releases a great deal of heat. Pour acid slowly into a larger volume of water and the water carries that heat away. Pour water onto concentrated acid and the heat is dumped into the small amount of water sitting on the surface, which can boil instantly and throw acid out of the container.
- Hot glassware looks exactly like cold glassware. No colour change, no glow, no warning. Assume anything near a heat source is hot, and use tongs or a clamp.
- Never heat a sealed container, and never seal a reaction that makes a gas. A gas that cannot expand raises the pressure until something gives, and what gives is glass. If a procedure produces a gas, the system stays open or vented — always.
- Point the open end of a heated test tube away from yourself and from everyone else. Heat it along its length rather than at one spot, and move it in and out of the flame.
- Waft, do not sniff. Cup a hand over the container and draw the air toward your face.
- Never return unused chemical to the stock bottle. Take what you need; the excess is disposed of as directed. One contaminated stock bottle spoils every class after yours, and occasionally does much worse than that.
- Know the disposal route before you start. Which waste container, or the sink with plenty of water, and it is not your judgement call — it is written in the investigation or I tell you. Nothing goes down the drain by default.
- Read the label twice — reaching for it, and again before pouring. The two bottles that look alike are always beside each other.
- Nothing enters your mouth. No eating, no drinking, no gum, no tasting, and wash your hands before you leave whether or not you think you touched anything.
Concentration is part of the hazard
Grade 10 could mostly treat a substance as safe or unsafe. Chemistry cannot, because the same substance is a different problem at a different concentration, and this course does more work with solutions than last year did.
Everything in this room is a dilute school reagent unless I hand it to you and say otherwise. That is a deliberate choice and it is what makes the procedures here reasonable. It also means two things you must not do:
- Do not scale a procedure up because it seems to be working. Volume, concentration, and rate of addition are all safety variables, and a reaction that is gentle at 10 mL is not necessarily gentle at 100.
- Do not assume the household version of a substance behaves like ours. The bottle under a sink at home is frequently far more concentrated than anything you will meet here, and household products are never mixed together — some combinations release toxic gases, and there is no version of that experiment that belongs anywhere.
Before you start, know where these are
- Eyewash station — and that it runs for a full fifteen minutes
- Safety shower, and how to pull it
- Fire extinguisher and fire blanket
- First-aid kit and the spill kit
- The waste containers, and which is which
- The fume hood, and how to tell it is running
- The nearest exit, and the one you would use if that exit is the problem
Report everything, immediately
Every spill, break, cut, burn, splash, and “I think some got on my hand”. A small event handled in the first thirty seconds is nothing. The same event hidden for ten minutes becomes an incident report and sometimes an injury. You will never be in trouble for reporting an accident — the only thing that ends lab privileges here is not reporting one.
Related: Safety in the Lab for the agreement itself, Acids and Bases for what is happening chemically when a corrosive does its damage, Measuring Well for handling the glassware, and What to Bring for what you need on a lab day.
Curriculum connection
A1.4
apply knowledge and understanding of safe laboratory practices and procedures when planning investigations by correctly interpreting Workplace Hazardous Materials Information System (WHMIS) symbols; by using appropriate techniques for handling and storing laboratory equipment and materials and disposing of laboratory materials; and by using appropriate personal protection (e.g., wearing safety goggles)
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