Working in heat often gets treated as a test of character rather than a hazard. Every other danger on a job has a control measure, a procedure, and someone whose signature goes on it. Hot weather gets a joke about the forecast and a promise to knock off early. Australian work health and safety law puts obligations on your employer for hot conditions, and it gives you a say in when a shift stops.
What Legally Counts as Working in Heat
Working in heat covers any job where your surroundings or your workload push your body past the temperature it can stand. Safe Work Australia treats this as a workplace hazard, and WHS Regulations require your employer to make sure that if you must work in extreme temperatures that you can do so without risk to your health and safety.
Weather is one source. Hot machinery, furnaces, ovens, steam, and hot surfaces all add heat to a workplace. Radiant heat from a concrete slab or a metal roof adds more again. Indoor work brings the same risk. Commercial kitchens, laundries, plant rooms, and roof cavities all get hot enough to cause heat illness.
How Heat Builds in the Body Across a Shift
Your body holds a standard average temperature of around 37 degrees Celsius. Working in heat raises this number unless the heat can leave your body at the same rate you absorb it.
When your body heats, blood vessels near your skin widen, sweating begins, and both your breathing rate and heart rate rise. Sweat cools your skin through evaporation, but costs you fluid that goes unreplaced and reduces your blood volume. Your body then sends less heat to your skin, causing your core temperature to rise faster.
Repeated exposure across consecutive shifts can leave you with irritability, headaches, nausea, loss of appetite, and lethargy towards the end of a shift or during the next one. Workplace Health and Safety Queensland refers to this as a heat hangover.
Conditions That Affect the Heat in Your Workplace
The forecast is just one factor. Most people feel comfortable between 20 and 27 degrees Celsius at 35 to 60 percent relative humidity. The conditions on a worksite regularly fall well outside that range even when the temperature reads as lower. Other factors that affect your heat at work include:
Radiant heat from working in heat on a metal roof, a concrete slab, or beside a furnace.
High humidity means sweat cannot evaporate as easily, which raises your core temperature.
A breeze can move heat away from your skin, and a confined space removes that entirely.
Your workload. Physical exertion over long periods raises the risk of heat illness even in moderate conditions.
Who Feels the Heat First on a Worksite
Identical conditions affect workers differently, and the risk of heat illness while working in heat is higher for workers who:
Are under 25 or over 55
Are pregnant
Have diabetes, a history of heart disease, obesity, or a fever
Take diuretics or non-medical drugs
Have suffered from heat-related illness before
Are on a fluid-restricted diet
Are returning to work after an absence of a week or more
Acclimatisation shifts the odds without removing them. A worker who has acclimatised sweats more efficiently and holds a normal body temperature more easily. There is a limit to how far any person’s body adapts, so your employer cannot rely on acclimatisation as a control measure, and an acclimatisation program should be set up with an occupational hygienist.
Early Signs of Heat Strain
The earliest signs of strain from working in heat are both physical and mental.
Thirst, dry lips and tongue, and reduced or dark urine output all point to dehydration. Heat rash appears as an itchy rash of small raised red spots on your face, neck, back, chest, or thighs. Dizziness and faintness follow reduced blood flow to your brain. Heat sends more blood to your skin and pools it in your legs, and your blood pressure can drop suddenly when you stand or rise from sitting.
Clumsiness, slower reactions, slowed thinking, and difficulty concentrating are signs you should recognise. Heat makes complex tasks harder to hold together, and mistakes follow.
Heat Cramps, Heat Exhaustion, and Heat Stroke
Heat-related illness is progressive. Heat cramps are painful, sometimes incapacitating spasms in your abdomen, arms, or legs. They follow the loss of salt and water through heavy sweating during demanding physical work.
Heat exhaustion is a serious condition. Excessive sweating in a hot environment reduces your blood volume, and the warning signs include paleness, heavy sweating, rapid heart rate, muscle cramps, headache, nausea, vomiting, dizziness, and fainting. Your skin can feel cool, pale, and clammy while sweating continues.
Heat stroke is a medical emergency. Your body can no longer cool itself, your internal systems begin to shut down, and liver, kidney, muscle, and heart damage can follow. Sweating may stop altogether, and your skin can turn pink, warm, and dry, or cool and blue.
Severe symptoms include disorientation, impaired judgement, mental confusion, rapid or short breathing, a rapid weak pulse or heart palpitations, tingling or numbness in fingers or toes, visual disturbance, vomiting, an unwillingness to drink, seizures, collapse, and unconsciousness. Not all of them appear in any one person. Delayed treatment can result in death.
First Aid for Heat Illness on Site
First aid for heat illness while working in heat comes down to cooling and rehydration. Call 000 immediately for suspected heat stroke or severe heat exhaustion, and evacuate the worker by ambulance. Update the ambulance operator if the worker seizes or loses consciousness, and follow every direction given.
Move the worker to a cool place with circulating air while you wait. Lie them flat, remove unnecessary clothing including PPE, and loosen anything tight. If a bath of cold water is available and safe to use, immerse the worker from the neck down at 1 to 7 degrees Celsius for 15 minutes, and watch them continuously for any change in consciousness. Otherwise, combine splashing or sponging cool water onto their skin, suspending sheets around their body and directing gentle airflow from a fan through the space, and applying cold packs or wrapped ice to their neck, groin, and armpits.
Give an electrolyte drink with sugar only to a worker who is fully conscious, and sit them up before they drink. If shivering starts, stop cooling and cover them until it passes, then resume.
Conditions short of an emergency are handled on site. Medical advice follows in every case where symptoms fail to improve or turn severe.
Stop the activity for heat cramps, let the worker rest in a cool place until they recover, give an electrolyte solution, and seek medical attention if the cramps continue beyond an hour
Lie a worker who has fainted flat immediately with their legs slightly raised, leave their head down, then treat as for heat stroke and follow medical advice
Move a worker with heat rash somewhere cooler and less humid, keep the affected skin dry, remove unnecessary clothing, and apply a cold compress
Give water for dehydration, skip caffeinated, carbonated, and alcoholic drinks along with salt tablets, and replace electrolytes where the heat or the fluid loss is extreme
Water, Rest, and Shade Across a Hot Shift
Cool water, rest breaks, and shade are the controls that apply to the daily run of working in heat. Your employer must give you access to cool drinking water, and to electrolyte solutions where sweat loss is heavy.
Drink small volumes as frequently as you can during work. Thirst is satisfied before your fluid loss has been fully replaced, so fluid intake guided by thirst alone falls short. Sports drinks containing salt and potassium replace what water on its own cannot.
Rest areas belong as close to the work as possible. Air-conditioned or shaded break areas let your core temperature drop, and removing protective clothing during a break speeds that up. Your employer should encourage the crew to hydrate at the start of a shift and rehydrate between shifts.
Scheduling reduces exposure across the whole shift. Physically demanding tasks belong in the cooler part of the day, and hot enclosed spaces such as roof cavities are best entered first thing in the morning. Work at ground level cuts the effort spent climbing stairs and ladders. Modified targets and work rates let workers pace themselves.
Clothing and PPE in Hot Conditions
What you wear while working in heat changes how much heat your body sheds. Clothing that blocks the evaporation of sweat or stops air flow across your skin raises your risk of heat illness, and heavy protective clothing and masks trap heat against your body.
Loose fitting, lightweight, breathable clothing helps. Light colours, particularly white and reflective fabrics, absorb less radiant heat. Cotton undergarments and cotton glove liners under regular gloves hold less heat against your skin, and vented safety eyewear and respirators with an exhalation valve help where they are safe to use.
Where PPE raises your heat risk, additional control measures belong alongside it. Your employer should account for the type of PPE, how long you wear it, your work rate, your acclimatisation, and the conditions, then extend break times to match.
Sun protection covers two hazards at once. Outdoor workers receive five to ten times more ultraviolet radiation each year than indoor workers, and long pants with a collared, long-sleeved shirt cover the skin that takes the worst of it. A broad brimmed hat needs a brim of at least 7.5 cm, and a bucket hat an angled brim of at least 6 cm. A hard hat takes a brim attachment for the same purpose.
Sunscreen, sunglasses, and shade complete the set. No sunscreen blocks all solar UV. It belongs alongside a hat, clothing, and shade.
Employer Duties for Heat Under Australian WHS Law
Your employer’s duties for working in heat come from the model Work Health and Safety Act and Regulations, adopted across Australian states and territories. A person conducting a business or undertaking, the PCBU, must eliminate risks to health and safety so far as is reasonably practicable, and minimise what cannot be eliminated.
The hierarchy of control applies to heat as it does to any other hazard. Elimination comes first, through cancelling or rescheduling tasks until conditions cool. Substitution, isolation, and engineering controls follow, covering machine work in place of manual work, barriers between workers and hot machinery, shade tents, air conditioning, insulation and cladding on radiant heat sources, fans, local exhaust ventilation, and cool drinking water. Administrative controls come next, covering scheduling, supervision, and training. PPE handles what remains, and your employer must review every control measure in place for new risks it introduces.
Training is part of the duty. Safe Work Australia expects workers to be trained to identify and report heat hazards, recognise symptoms in themselves and others, call for assistance, modify work intensity, take more regular breaks, drink enough water, recognise the dangers of diuretic drinks, and understand acclimatisation along with the risks associated with heat and alcohol or drugs.
When Heat Means Stopping Work
Australian WHS law sets no maximum temperature at which working in heat must stop. A single stop-work temperature cannot account for humidity, air flow, the intensity and duration of the work, or whether workers are physically fit and acclimatised. The obligation to eliminate or minimise the risk stands in its place, and it can require cancelling or rescheduling tasks until conditions cool.
You control your own right to stop. The WHS Act lets a worker cease or refuse work where they have a reasonable concern that carrying it out would expose them to a serious risk to their health or safety from an immediate or imminent exposure to a hazard. You must notify your PCBU as soon as practicable, and you must remain available for suitable alternative work within your skills and capabilities until you can resume normal duties.
Health and safety representatives hold a wider power. A trained HSR can direct workers in their work group to cease unsafe work after consulting the PCBU and failing to resolve the matter. If the risk is so serious and immediate that consultation is not reasonable first, the HSR can give the direction straight away, verbally or in writing, and consult afterwards. A cessation direction stays in force until the HSR withdraws it in writing, an inspector resolves the issue or issues a prohibition notice, or the industrial relations commission deals with the dispute.
Heat Safety and White Card Training
Working in heat is never just one number. Nobody on site is protected by the thermometer. The same understanding has to be in every head on a job, in place before the first hot day of the season. Our white card course leaves you able to spot a hazard, report it in terms a supervisor has to act on, and hold your employer to what they owe you before conditions turn against you.
FAQs
Can Long-Sleeved Clothing Cause Heat Illness?
No. Long clothing on its own does not cause heat-related illness.
What Injuries Besides Heat Illness Come From Hot Conditions?
Burns and slips are two of the biggest. Contact with hot surfaces and tools causes burns on a hot site. Heavier sweating leaves hands damp, and damp hands lose grip on sharp tools.
How Can I Assess Heat Stress Risk on a Site?
Workplace Health and Safety Queensland publishes a heat stress basic calculator that anyone with working knowledge of the area and process can use, with no measuring instruments required.
