1. Purpose

The purpose of the Thermal Exposure Program is to protect all employees from hazards associated with extreme temperature conditions, including both heat stress and cold stress. This program establishes the procedures, responsibilities, controls, training, and emergency measures required to ensure safe working conditions in environments with elevated or reduced temperatures.

2. Scope

This program applies to all employees, contractors, temporary staff, and visitors who may be exposed to hot or cold environments due to job tasks, workplace conditions, or seasonal weather patterns. It applies to both indoor and outdoor worksites.

3. Responsibilities

3.1 Management

• Implement, maintain, and annually review the Thermal Exposure Program.
• Provide required resources, including training, PPE, shaded/warm rest areas, hydration, and engineering controls.
• Ensure supervisory staff enforce all temperature-related safety practices.
• Ensure First Aid responders are trained in heat and cold emergency care.

3.2 Supervisors

• Monitor environmental conditions (temperature, humidity, wind chill, radiant heat, workload).
• Enforce work–rest schedules and hydration plans.
• Closely monitor new or returning workers undergoing acclimatization.
• Identify early signs and symptoms of heat and cold stress and take immediate corrective action.
• Document temperature-related incidents or near misses.

3.3 Employees

• Follow all safe work procedures.
• Use required PPE properly (cooling vests, thermal clothing, gloves, etc.).
• Stay hydrated and take scheduled rest breaks.
• Report early signs of heat or cold stress in themselves or coworkers.

4. Hazard Identification

Employees may be exposed to thermal hazards in environments such as roofs, bridges, high structures, open cabs, refrigerated rooms, or any outdoor work exposed to weather extremes.

4.1 Heat Hazards

• Heat stroke
• Heat exhaustion
• Heat cramps
• Dehydration
• Reduced cognitive performance

4.2 Cold Hazards

• Hypothermia
• Frostbite
• Trench foot
• Reduced dexterity and motor skills

4.3 Environmental Factors

• Ambient temperature
• Humidity
• Wind speed / wind chill
• Radiant heat
• Physical activity and workload

5. Controls

5.1 Engineering Controls

• Cooling fans, ventilation, air conditioning
• Radiant heat barriers/shields
• Heated shelters/work areas
• Insulated tools and equipment

5.2 Administrative Controls

• Work–rest cycles based on temperature or WBGT/heat index/wind chill.
• Hydration schedule: 250–500 ml water every 15–20 minutes in hot conditions.
• Job rotation to reduce prolonged exposure.
• Providing warm sweet fluids and regular hot-break intervals in cold conditions.

5.3 Personal Protective Equipment (PPE)

For Heat:

• Cooling vests, hats, moisture-wicking and light-coloured clothing
• Breathable fabrics

For Cold:

• Insulated gloves, boots, and thermal jackets
• Hats, balaclavas, face protection
• Waterproof/windproof outer layers
• Multiple clothing layers (including polypropylene base layers)

6. Heat Stress Prevention Program

6.1 Hydration

• 250–500 ml of water every 15–20 minutes regardless of thirst.
• Electrolyte drinks provided during sustained sweating.
• Avoid energy drinks, alcohol, and excessive caffeine.

6.2 Rest and Shade

• Mandatory rest breaks based on environmental conditions.
• Shaded or cooled areas must be available for recovery.
• Workers may take additional breaks if early symptoms arise.

6.3 Acclimatization

• Increased supervision during acclimatization.

6.4 Clothing and PPE

• Lightweight, breathable garments.
• Cooling vests where necessary.

6.5 Planning

• Use mechanical aids to reduce physical strain.
• Increase staffing for task rotation.

7. Cold Stress Prevention Program

7.1 Understanding Cold Stress

Cold exposure can result from natural weather or artificial environments (refrigeration, unheated cabs, steel structures, etc.). When the body cannot maintain core temperature, cold-related illnesses can occur.

7.2 Hypothermia

Symptoms

• Shivering (begins at ~35°C core temperature)
• Blue lips/fingers
• Confusion, poor coordination
• Slow breathing/heart rate
• In severe cases: unconsciousness, no shivering, irregular pulse

First Aid

• Move to warm shelter; remove wet clothing.
• Warm torso first (neck, chest, abdomen, groin).
• Provide warm, sweet drinks if conscious.
• Apply direct body heat or safe warming devices.
• Monitor breathing; administer artificial respiration if necessary.
• Seek medical assistance immediately.

7.3 Frostbite

Symptoms

• Waxy-looking skin, numbness
• Sharp/prickling sensation
• Hard, frozen tissue in severe stages
• Blistering (takes ~10 days to subside)

First Aid

• Warm gradually using body heat—do not rub.
• Do not thaw hands/feet unless refreezing is impossible.
• Apply sterile dressings; get medical attention.

7.4 Risk Factors

• Heart disease
• Asthma/bronchitis
• Diabetes
• Vibration/white finger disease
• Certain medications (as advised by a healthcare provider)

7.5 Clothing Requirements

• Wear multiple layers to trap insulated air.
• Polypropylene or synthetic base layers for moisture wicking.
• Waterproof or water-repellent outer layers when wet conditions exist.
• Hats, hoods, and face protection as needed.
• Footwear must allow for adequate sock layering without constriction.
• Workers who overheat should open jackets but keep hands/head protected.

7.6 Exposure Limits

Ontario has no legislated limits.
ACGIH and Saskatchewan guidelines apply, using temperature/wind chill thresholds to determine safe exposure durations.