1.2 WHMIS, GHS, Safety Data Sheets (SDS) & Chemical Safety

Gas technicians handle hazardous materials including compressed fuel gases, thread sealants, solvent cements, flux pastes, cutting lubricants, and refrigerants. Preventing acute poisoning, occupational illness, fires, and explosions requires thorough knowledge of the Workplace Hazardous Materials Information System (WHMIS) and rigorous chemical safety procedures.

The WHMIS & GHS Regulatory Architecture in Ontario

WHMIS is Canada's national hazard communication standard. It is governed federally by the Hazardous Products Act (HPA) and Hazardous Products Regulations (HPR), administered by Health Canada. In Ontario, WHMIS is enforced under the Occupational Health and Safety Act (OHSA) and Ontario Regulation 860 (Workplace Hazardous Materials Information System).

WHMIS is aligned with the Globally Harmonized System of Classification and Labelling of Chemicals (GHS), standardizing hazard classifications, pictograms, label wording, and safety data sheets across international borders.

The Three Pillars of WHMIS

WHMIS functions through three interdependent components:

1. Hazard Labels: Warning labels affixed to containers alerting workers to key physical and health risks.
2. Safety Data Sheets (SDSs): Standardized 16-section technical documents detailing chemical properties, toxicology, first-aid, safe handling, and spill response.
3. Worker Education and Training: Mandatory instruction divided into General Education (principles of WHMIS, hazard classes, pictograms, and label formats) and Site-Specific Training (practical instruction on specific jobsite chemicals, mandatory PPE, decanting rules, emergency eye wash locations, and spill cleanup).

Employers must ensure all hazardous products are labelled, current SDSs are accessible to all workers on every shift without barriers, and training is reviewed annually.

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WHMIS Hazard Pictograms & Classification

WHMIS classifies hazards into Physical Hazards (flammability, compressed gases, reactivity) and Health Hazards (toxicity, irritation, carcinogenicity).

Pictograms consist of a black symbol on a white background inside a solid red square set on a point (diamond border). The Biohazard pictogram retains a black trefoil in a round black border.

Signal Words

WHMIS labels use standardized Signal Words to indicate hazard severity:

• "Danger": Used for higher-severity hazard categories (e.g., Category 1 Flammable Gas).
• "Warning": Used for lower-severity hazard categories (e.g., Category 2 Flammable Gas). If both apply to different hazard classes on the same product, only "Danger" appears on the label.

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Supplier Labels vs. Workplace Labels

Ontario WHMIS legislation enforces two distinct types of product labels:

The Supplier Label

Created and affixed by the manufacturer or distributor. Under federal regulations, it must be bilingual (English and French) and contain six mandatory elements:

1. Product Identifier: Brand or chemical name matching the SDS.
2. Initial Supplier Identifier: Name, Canadian address, and phone number of the manufacturer or importer.
3. Hazard Pictograms: GHS pictograms in red diamond borders.
4. Signal Word: "Danger" or "Warning".
5. Hazard Statements: Standardized phrases describing hazard nature (e.g., "Extremely flammable gas").
6. Precautionary Statements: Prescribed phrases covering prevention, response, storage, and disposal.

The Workplace Label

Created and applied on-site by the employer or technician. Under O. Reg. 860, a workplace label is legally required:

1. When a chemical is decanted from its original container into a secondary container (e.g., pouring cutting oil from a 20-litre drum into an oiler squeeze can).
2. When the original supplier label becomes torn, defaced, or illegible.
3. When a chemical mixture is formulated on-site.

A compliant Workplace Label requires three mandatory elements:

1. Product Identifier: Matching the product name on the SDS.
2. Safe Handling Precautions: Required PPE and handling instructions (e.g., "Wear chemical splash goggles and nitrile gloves; use in ventilated area").
3. Reference to the SDS: An explicit statement stating that a Safety Data Sheet is available in the workplace.

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Safety Data Sheets (SDSs): The Standardized 16-Section Structure

Under GHS and WHMIS, all SDSs follow a standardized 16-section format. Suppliers must update an SDS within 90 days of receiving significant new hazard data.

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Chemical Handling, Cylinder Safety & Fire Protection

Gas technicians work constantly with high-pressure gas cylinders and flammable materials.

Compressed Gas Cylinder Protocols

• Upright Storage & Securing: All cylinders must be stored upright and secured to walls or carts using non-combustible chains or heavy-duty straps.
• Valve Protection Caps: Steel caps must be hand-tightened over valves whenever cylinders are moved, transported, or not connected to a regulator.
• Separation of Fuel and Oxidizing Gases: Fuel gas cylinders (acetylene, propane) must be stored at least $6\text{ metres}$ ($20\text{ feet}$) away from oxidizing gas cylinders (oxygen), or separated by a non-combustible barrier wall at least $1.5\text{ metres}$ ($5\text{ feet}$) high with a fire-resistance rating of at least $30\text{ minutes}$.
• Acetylene Orientation Rule: Acetylene is dissolved in liquid acetone inside a porous mass. Cylinders must always remain upright. If laid horizontally, acetone will enter the valve, dissolve regulator seals, and cause flashback explosions. If transported horizontally, stand upright for at least as long as it was horizontal (minimum $1\text{ hour}$) before opening the valve.

Fire Chemistry & Extinguisher Selection

Combustion requires four elements, represented by the Fire Tetrahedron: Fuel, Oxygen, Heat, and an Uninhibited Chemical Chain Reaction. Removing any single element extinguishes the fire.

• Class A: Ordinary combustibles (wood, paper, textiles). Extinguished with water or multi-purpose dry chemical.
• Class B: Flammable liquids and fuel gases (natural gas, propane, solvents, oils). Extinguished with carbon dioxide ($CO_2$) or dry chemical. Never extinguish a burning gas leak unless the fuel supply can be shut off immediately.
• Class C: Energized electrical equipment (motors, circuit boards, transformers). Extinguished with non-conductive agents ($CO_2$, dry chemical). Never use water due to fatal electrocution hazards.
• Class D: Combustible metals (magnesium, titanium). Extinguished with dry powder agents.
• Class K: Commercial cooking media (vegetable oils, animal fats). Extinguished with wet chemical agents.

The PASS Extinguisher Technique

Deploy portable fire extinguishers using the four-step PASS procedure:

1. P - Pull: Pull the safety locking pin, breaking the plastic tamper seal.
2. A - Aim: Aim the nozzle at the base of the fire, where fuel is burning.
3. S - Squeeze: Squeeze the operating lever to release the extinguishing agent.
4. S - Sweep: Sweep the nozzle smoothly from side to side across the base of the fire until extinguished. Stand $2\text{ to }3\text{ metres}$ ($6\text{ to }10\text{ feet}$) back with an unobstructed escape path behind you.

Inspect extinguishers monthly: verify the pressure gauge needle is in the green zone, the safety pin is intact, the nozzle is unobstructed, the shell has no dents or severe rust, and the inspection tag is signed and dated.