DoAssignment study guide

A1.4 · Plan investigations using safe laboratory practices and WHMIS

Learn to plan investigations using safe laboratory practices and whmis through clear examples and targeted practice.

Ontario Grade 12 Chemistry

Scientific Investigation Skills and Career Exploration

SCH4U study topic A1.4: safe laboratory practices and WHMIS

A chemistry investigation can look routine and still involve hazards. A liquid may irritate skin, a powder may create harmful dust, and heated glassware may cause burns. Safe work begins before materials are handled. You need to understand the task, find reliable hazard information, follow your teacher’s instructions, and plan how to prevent exposure. WHMIS—the Workplace Hazardous Materials Information System—helps people communicate information about hazardous products. It does not replace training, supervision, or your school’s safety rules. This lesson focuses on planning: do not begin an investigation until the teacher has approved the procedure and the safety plan.

What you will learn

Identify safety questions to resolve before beginning a chemistry investigation.
Use WHMIS labels and Safety Data Sheets (SDSs) to find hazard and precaution information.
Plan suitable controls, personal protective equipment, waste handling, and emergency steps.
Explain why an investigation must be changed or paused when a hazard cannot be controlled.

1. Start with the question and the hazards

Before SCH4U, you learned to follow laboratory instructions, use equipment carefully, and report unsafe conditions. Those habits are the starting point here. An investigation plan adds a deliberate check of what could cause harm and how to reduce the chance of harm.

A hazard is something that can cause injury or illness, such as a corrosive liquid, hot plate, broken glass, or slippery spill. Risk is the chance that harm will occur in a particular situation. A hazardous material does not cause harm in every circumstance; the task and the way it is handled matter. Planning aims to remove a hazard where possible or reduce exposure to it.

First, state the investigation question and outline the proposed steps. List every material and piece of equipment, including cleaning products and materials used for disposal. Note actions that may create additional concerns, such as heating, mixing, transferring, or producing dust. Do not assume that a small quantity or a familiar substance is automatically safe.

Next, check the school’s written procedures and ask the teacher about any unclear step. Students should not independently substitute a chemical, change the procedure, or decide that a control is unnecessary. If the required equipment is missing, a label cannot be read, or the procedure seems inconsistent with the safety directions, stop and ask before proceeding.

Identify materials, equipment, and potentially hazardous steps before work begins.
Follow teacher approval and school procedures; do not improvise changes.
Pause and ask when a hazard or required control is unclear.

2. Use WHMIS information correctly

WHMIS provides a common way to communicate hazards of hazardous products in Canadian workplaces and educational settings. A workplace label and an SDS are key information sources. Your teacher may also provide school-specific directions. Use the container label for the product actually supplied; never rely on a similar-looking container or memory.

A WHMIS label can include a product identifier, pictogram, signal word, hazard statement, and precautionary statements, along with supplier information where required. A pictogram is a symbol that signals a type of hazard. The signal word is either “Danger” or “Warning”; it indicates the relative level of hazard within the applicable hazard class. A hazard statement describes the nature of a hazard. A precautionary statement gives advice for prevention, response, storage, or disposal. Read the words as well as recognizing the pictogram.

An SDS is a Safety Data Sheet. It gives detailed information about a hazardous product. For planning, consult the sections that describe hazards, first aid, handling and storage, exposure controls and personal protection, accidental release measures, and disposal. Check the product identity so that the SDS matches the container. If it does not match, or the information is unavailable or unclear, tell the teacher and do not use the product.

Use the hazard information to decide what controls are needed for the actual task. Controls are steps or equipment that reduce exposure or injury. Examples include using a smaller quantity when the approved procedure permits it, working in the location specified by the teacher, keeping containers closed when not in use, and using suitable protective equipment. Follow the SDS and school directions together; do not select controls by guessing from a pictogram alone.

Match the label and SDS to the exact product being used.
Read hazard and precaution statements, not just pictograms.
Use the SDS and school procedures to plan controls and emergency responses.

3. Build the safety plan before the procedure

A useful plan connects each hazard to a control. For example, if a step could splash a liquid, identify how to prevent splashing and what eye protection is required by the teacher and procedure. If glassware could break, plan where it will be placed and how broken glass will be reported and handled under school rules. Do not pick up broken glass with bare hands.

Personal protective equipment, or PPE, is equipment worn to reduce exposure. Depending on the approved procedure, it may include splash goggles, a lab coat or apron, and suitable gloves. PPE must fit and be used as directed. Gloves are not a reason to touch your face, personal belongings, or shared surfaces. Wash hands after laboratory work, even if gloves were worn. Wear closed-toe footwear and secure loose hair or clothing as required by school rules.

Plan the work area and the end of the investigation. Keep pathways clear, label containers as directed, and use only the quantities and equipment approved by the teacher. Know where the eyewash station, safety shower, spill supplies, fire-safety equipment, and exits are, as applicable to the room. Learn how to alert the teacher and follow the school’s emergency procedure. Do not attempt cleanup or first aid beyond your training and the teacher’s instructions.

Waste handling is part of planning, not an afterthought. Check the teacher’s directions and relevant SDS information before disposing of anything. Never assume that a material may go down the drain or into ordinary garbage. Keep waste in the designated container and do not mix waste streams unless specifically instructed. Afterward, leave equipment and the bench as directed, report spills or breakage, and wash your hands.

Pair each identified hazard with a practical control.
Use PPE as directed; it does not make unsafe handling acceptable.
Plan emergency actions and waste handling before starting.

4. Review, communicate, and decide whether to proceed

Before work begins, review the plan with the teacher or group. Each person should know the procedure, the important hazards, the controls, the location of emergency equipment, and how to report a problem. Clear communication matters because one person’s action can affect everyone nearby.

Make a final go-or-pause decision. Proceed only when the teacher has approved the plan, the required information and equipment are available, and the specified controls can be followed. If circumstances change—for example, a container is damaged, a spill occurs, or equipment stops working—stop the affected work, alert the teacher, and follow directions. Do not conceal an error or try an unapproved fix.

A strong plan is specific to the investigation. “Be careful” is not enough. A useful plan names the concern, the action that reduces it, the protective equipment required, the emergency response, and the approved waste route. This approach supports safe decisions without treating WHMIS as a checklist that replaces judgment or supervision.

Share the plan so everyone understands their role.
Proceed only with approval and controls that can actually be followed.
Stop, report, and ask for direction when conditions change.

Worked example

Planning a proposed investigation

A class is considering an investigation that compares how quickly two approved solid samples dissolve in water. The teacher has not yet approved the procedure. Describe the safety-planning steps the group should take before deciding whether to proceed.

Clarify the proposed work
Write the question and draft steps, then list the exact samples, water, containers, and any equipment. Do not assume the samples are harmless because they are solids or because water is familiar. The teacher must approve the materials and procedure before the investigation begins.
Check hazard information
Read each supplied product label and consult the matching SDS when available. Look for hazards from contact, swallowing, or breathing dust, as well as handling, first-aid, spill, and disposal directions. If a sample is unidentified or its information is missing, pause and ask the teacher rather than guessing.
Choose controls with the teacher
Discuss how to prevent dust or splashes and which PPE and work location the approved procedure requires. Keep samples contained and use only the approved quantities. Identify how to report a spill or exposure and which waste container to use. Follow school procedures; do not invent a cleanup or disposal method.
Make the proceed decision
The group may proceed only after teacher approval and only if the required information, equipment, and controls are in place. If any hazard remains unclear or a control cannot be followed, explain the concern and wait for revised instructions. This plan describes proposed work; it does not claim that the investigation was carried out.

Answer: The group should identify exact materials and steps, check matching labels and SDSs, agree on controls and PPE with the teacher, plan emergency and waste procedures, and wait for approval. Unclear hazards or unavailable controls mean the investigation should not begin.

Check: This plan addresses hazards before exposure and does not assume that a familiar material or a small sample is automatically safe.

Common mistakes and how to avoid them

Looking only at a pictogram and guessing what to do.

Correction: Read the full label and consult the matching SDS. Follow the teacher’s instructions for the specific task.

Treating gloves or goggles as permission to handle a material carelessly.

Correction: PPE is one control, not a substitute for safe procedure, supervision, or other required controls.

Waiting until the end to decide how to discard materials.

Correction: Check the approved waste route before beginning, and use only the designated container and directions.

Trying to clean a spill or repair a problem without telling anyone.

Correction: Stop, alert the teacher, and follow the school’s emergency procedure and your level of training.

Lesson summary

Plan safety before handling materials: identify the task, materials, equipment, and possible hazards.
Use the exact product label and matching SDS to understand hazards and precautions.
Agree on controls, PPE, emergency steps, and waste handling with the teacher.
Proceed only with approval; stop and report unclear or changing conditions.

Check your understanding

Question 1

The SDS for a sample cannot be matched confidently to the container. What is the safest next step?

Use a very small amount and rely on gloves.
Ask the teacher and do not use the sample until its identity and safety information are confirmed.
Search for a similar product and assume its directions apply.
Pour the sample into the sink before beginning.

Show answer and explanation

Ask the teacher and do not use the sample until its identity and safety information are confirmed.

The hazard information must match the actual product. Do not use an unidentified product or substitute another product’s information.

Question 2

When should a group plan the waste route for an investigation?

Before beginning, using teacher directions and relevant product information.
Only if waste is visibly coloured.
After placing all waste in ordinary garbage.
Whenever each student thinks disposal is convenient.

Show answer and explanation

Before beginning, using teacher directions and relevant product information.

Waste handling is part of the safety plan. Students should follow the approved directions rather than assume a disposal route.

Question 3

A spill occurs during an approved investigation. What should a student do first?

Hide it so the group can finish on time.
Wipe it up immediately with paper towels, regardless of the material.
Stop the affected work, alert the teacher, and follow the school’s directions.
Ask another student to handle it without protective equipment.

Show answer and explanation

Stop the affected work, alert the teacher, and follow the school’s directions.

The response depends on the material and school procedure. Alerting the teacher avoids untrained or unsafe cleanup.

Key terms

Hazard: Something that can cause injury or illness.
Risk: The chance that harm will occur in a particular situation.
WHMIS: The Workplace Hazardous Materials Information System, which communicates information about hazardous products.
SDS: A Safety Data Sheet containing detailed information about a hazardous product.
PPE: Personal protective equipment worn to reduce exposure or injury.
Control: A step or piece of equipment used to reduce exposure or injury.

Continue through SCH4U

View the complete SCH4U Ontario Grade 12 Chemistry curriculum and lessons

About this lesson and its review

Published by DoAssignment. This reviewed lesson follows Ontario Grade 12 Chemistry (SCH4U), expectation A1.4. It is a study resource, not an official curriculum publication.

Before publication, content is checked for structure, mathematical or chemical notation, calculations, course boundaries, and readability. Errors can still occur, so corrections are welcomed.

Official curriculum reference

Report a correction or ask a question