Heat Stress at Work: Australian Employer Obligations for Managing Heat Hazards

Australia has one of the world's harshest climates, and heat is a genuine — and frequently underestimated — workplace hazard. Workers in construction, agriculture, outdoor maintenance, emergency services, warehousing, and kitchen environments are all at risk of heat-related illness.

As a person conducting a business or undertaking (PCBU), you have a duty under the Work Health and Safety Act to manage heat as a workplace hazard. This is not a soft obligation — failures to control heat have resulted in worker deaths and significant prosecution.

Heat as a WHS Hazard

Heat is a psychophysical hazard — it affects the body's physiological function and can cause a spectrum of conditions from heat cramps and heat exhaustion to heatstroke, which can be fatal.

Under the WHS legislation, the obligation to ensure health and safety "so far as is reasonably practicable" clearly extends to climatic and environmental conditions, including heat. Safe Work Australia has published specific guidance on heat stress.

Who Is at Risk?

Any worker exposed to high temperatures — ambient or generated by equipment or processes — is potentially at risk. High-risk groups and settings include:

• Outdoor workers: Construction, agriculture, maintenance, grounds-keeping, waste collection
• Kitchen workers: Professional cooks and kitchen hands in commercial kitchens
• Warehouse workers: Non-air-conditioned storage facilities in summer
• Manufacturing workers: Environments with high process heat (bakeries, foundries, glass, ceramics)
• Emergency services: Fire fighters, paramedics, SES workers in summer conditions
• Workers in personal protective equipment: Chemical handlers and others who must wear non-breathable protective equipment

Factors That Increase Heat Stress Risk

Not just ambient temperature — multiple factors combine to create heat stress risk:

• Air temperature: Ambient temperature above 28–30°C increases risk
• Radiant heat: Heat from the sun, hot surfaces, or equipment radiating heat
• Humidity: High humidity reduces the effectiveness of sweating and significantly increases risk even at moderate temperatures
• Air movement: Low air movement prevents evaporative cooling
• Physical workload: Heavy physical work generates body heat
• PPE: Personal protective equipment traps heat and humidity
• Duration of exposure: Even moderate heat becomes hazardous with extended exposure
• Individual factors: Workers unacclimatised to heat, with certain medical conditions (cardiovascular disease, diabetes), on certain medications, or who consume alcohol are at higher risk

Your WHS Obligations

Your obligations under the WHS Act include:

1. Hazard Identification

You must identify whether heat is a hazard in your workplace. This includes:

• Reviewing outdoor work conditions during summer months
• Assessing indoor conditions in environments with process heat or inadequate ventilation
• Identifying high-risk work periods (hottest part of the day, hottest months)

2. Risk Assessment

Assess the likelihood and severity of harm from heat exposure. Safe Work Australia's Heat Stress Calculator and similar tools help assess heat risk based on temperature, humidity, radiant heat, work intensity, and PPE.

The Heat Stress Index takes into account wet bulb globe temperature (WBGT) — a measure that combines temperature, humidity, wind, and solar radiation into a single figure.

3. Control Measures

Apply the hierarchy of controls to heat risk:

Elimination: If possible, eliminate work in hot conditions — for example, scheduling physically demanding outdoor work in cooler parts of the day or year.

Substitution: Replace high-heat equipment or processes with lower-heat alternatives where feasible.

Engineering controls:

• Air conditioning or ventilation in indoor workspaces
• Shade structures for outdoor workers
• Cooling equipment (misting systems, fans)
• Insulation of hot surfaces and equipment
• Rest areas with air conditioning

Administrative controls:

• Schedule heavy work in the early morning when temperatures are lower
• Introduce mandatory rest breaks during hot conditions
• Rotate workers in and out of hot environments
• Implement a "buddy system" for workers in high-risk conditions
• Acclimatisation programs for new workers or workers returning from leave
• Reduce work intensity during extreme heat
• Modify PPE requirements where possible to reduce heat load

Personal protective equipment: Heat-reflective clothing, cooling vests, personal cooling devices — but note that PPE is the last resort in the hierarchy, not the first response.

4. Monitoring

Monitor conditions — particularly temperature and humidity — in high-risk settings. Consider:

• Weather monitoring for outdoor work (temperature, humidity forecasts)
• Monitoring of indoor temperatures in high-risk spaces
• Monitoring workers for signs of heat illness

5. Information, Training, and Supervision

All workers in heat-risk environments must:

• Understand the signs of heat illness (heat cramps, heat exhaustion, heatstroke)
• Know to stay hydrated — cool water, not cold, and regularly, not waiting until thirsty
• Know what to do if they or a colleague show signs of heat illness
• Know to acclimatise gradually when returning to hot work environments
• Feel empowered to raise concerns and stop work in extreme conditions

Supervisors must be trained to recognise heat illness and to respond appropriately, including calling emergency services when heatstroke is suspected.

6. Emergency Procedures

Your emergency response procedures must cover heat-related illness. Heatstroke — core temperature above 40°C with confusion or loss of consciousness — is a medical emergency. Workers must know:

• When to call 000
• How to cool an affected worker while waiting for emergency services (cool water immersion, ice packs to neck, armpits, and groin)

Extreme Heat Events

Australia is experiencing more frequent and more severe heat events as a result of climate change. During extreme heat events — temperatures above 40°C, extended heatwaves — standard heat risk controls may be insufficient.

Consider stopping outdoor work during the hottest parts of extreme heat event days. The cost of stopping work is far less than the cost of a worker fatality or the prosecution that follows.

Some modern awards include provisions allowing workers to refuse to work in extreme weather conditions. Be aware of these provisions in your applicable award.

What Happens When Heat Injuries Occur

If a worker is injured as a result of heat exposure, the consequences include:

• Workers' compensation claim for the worker
• WHS incident reporting obligations (if serious injury or hospitalisation)
• WHS regulatory investigation
• Potential prosecution if inadequate controls were in place

In high-profile cases, WHS regulators have prosecuted employers for heat-related worker deaths, particularly where risk assessments were not conducted and no controls were in place.

How Reguladar Helps

Heat stress is just one of many WHS hazards that Australian businesses must manage. Reguladar tracks your WHS obligations across all hazard categories based on your industry and location — surfacing what controls you need to have in place and flagging changes to WHS guidance and legislation.

For businesses operating in northern Australia or in high-heat industries, Reguladar identifies the specific heat risk management obligations that apply to your context.

Know your WHS obligations before an incident occurs. Start your free compliance check at Reguladar and get your complete WHS compliance profile today.