It was cold, so they brought the heat inside. That’s the whole decision. No recklessness, no warning signs, no moment where anybody involved thought they were doing something dangerous — just four people in a house on a bitter winter night, trying to stay warm, making a choice that thousands of Australians would consider entirely reasonable. By the next morning, one of them was dead and the other three were in hospital.

We’ve written before about the emergencies that arrive with a scream and a crowd — the Coogee shark attack is the obvious example, where bystanders had roughly ninety seconds and one enormous decision to make. This is the opposite kind of emergency. It’s quiet. It doesn’t announce itself. And by the time the symptoms are obvious enough to act on, the person experiencing them may no longer be capable of acting at all.

What Happened in Mount Gambier

As ABC News report, on the 11th of July 2026, emergency services were called to a home on Penola Road in Mount Gambier, South Australia, just before 9am. The Metropolitan Fire Service initiated a HAZMAT response because of concerns about hazardous gas in the property — a decision that almost certainly protected the responders who went in.

Inside, firefighters found four unresponsive occupants. All four were carried out and handed to paramedics. A 55-year-old man died. The three others were taken to hospital.

Police believe the cause was carbon monoxide poisoning, and investigators have focused on heat beads — the charcoal briquettes millions of Australians have in a bag in the shed — that had been brought inside the house. As of writing, the matter remains under investigation and will be examined by the coroner, so the official findings are still to come. But the broad shape of it is depressingly familiar to anyone who has read a coronial report on carbon monoxide.

This is not the first time. Back in 2011, the NSW State Coroner examined the death of a man who died of accidental carbon monoxide poisoning after being exposed to fumes from barbecue briquettes indoors, and recommended that all barbecue charcoal briquettes sold in Australia carry a warning: never burn charcoal indoors, or in vehicles, or in tents. Fifteen years later, we are having the same conversation.

Why Heat Beads Indoors Are So Dangerous

Here’s the part that catches people out, and it’s worth sitting with for a moment.

Most of us have a rough mental model of “dangerous fire” that involves flames, smoke, heat and noise. Something you can see. Something that sets off an alarm. Heat beads that have burnt down past the flame stage tick none of those boxes. They glow gently. They give off very little smoke. They look, for all the world, like a tidy little source of warmth that has already done its scary bit and settled down.

That smouldering stage is precisely when carbon monoxide production peaks.

Carbon monoxide is a by-product of incomplete combustion — burning without enough oxygen to burn cleanly. A roaring, well-ventilated fire outdoors produces relatively little. A bed of glowing coals in a closed-up room, slowly starving of oxygen, produces a great deal. The room gets worse at supplying oxygen as the coals consume it, which makes the combustion less complete, which produces more carbon monoxide. It is a feedback loop, and it is running while you sleep.

And you cannot detect it. As NSW Health puts it plainly, carbon monoxide can’t be seen, smelled or heard. There is no warning smell like there is with natural gas, because there is no additive — this is a gas produced by a chemical reaction, not piped in by a utility with a legal obligation to make it stink.

It is also worth being blunt about something else: your smoke alarm will not save you. A smoke alarm detects particulate matter. Carbon monoxide is a gas, and a fairly clean-burning bed of coals produces very little smoke. The alarm sits on the ceiling, doing its job perfectly, detecting nothing.

What Carbon Monoxide Actually Does to the Body

Skip this bit if you like, but it explains why the symptoms are so easy to dismiss.

Your red blood cells carry oxygen around your body using a protein called haemoglobin. Think of haemoglobin as a bus with seats, and oxygen as the passengers who hop on at the lungs and hop off wherever they’re needed. Carbon monoxide binds to those same seats — but it binds roughly two hundred times more eagerly than oxygen does, and it doesn’t get off at its stop. So the buses keep circulating, full to capacity, delivering nothing.

Your blood volume is fine. Your heart is pumping. Your lungs are working. Your tissues are suffocating anyway.

The organs that scream first are the ones that use the most oxygen: the brain and the heart. That’s why the early signs are neurological — headache, confusion, poor judgement — and why the person affected often can’t reason their way to the door. The very organ they’d need to recognise the danger is the organ being starved first.

One more clinical detail worth knowing, because it trips up even trained responders: a fingertip pulse oximeter — the little clip that reads your oxygen saturation — can read reassuringly normal in a carbon monoxide patient. The device sees a haemoglobin molecule with something attached to it and counts it as “loaded”. It cannot tell the difference between an oxygen passenger and a carbon monoxide passenger. So a reading of 98% means nothing here. Treat the situation, not the number.

The Symptoms Everybody Misses

The single cruellest feature of carbon monoxide poisoning is that its early symptoms are indistinguishable from a bad winter’s night. You’ve had a few drinks, the heater’s been on, the house is stuffy, you’re tired and you’ve got a bit of a headache.

Or you’re being poisoned.

Early Signs

NSW Health lists the common symptoms as headache, nausea, vomiting and weakness. Add to that dizziness, shortness of breath on exertion, blurred vision, and difficulty concentrating. It presents, almost universally, as “flu-like” — which is why people go to bed instead of going outside.

Severe Signs

As exposure continues, people become dizzy or faint, lose consciousness, and can suffer seizures. In severe cases the outcome is permanent brain injury or death. There is no clean line between “a bit off” and “critical” — the slide can be quick, and it accelerates while the person is asleep and unable to notice.

The Red Flags That Should Make You Think “Carbon Monoxide”

Some patterns should switch your brain onto this immediately:

• More than one person in the house is sick at the same time. Viruses don’t usually drop four people in one night with identical symptoms.
• The pets are sick too. Smaller bodies, faster metabolisms — animals often show it first.
• Everyone feels better when they leave the house and worse when they come back. This is the classic pattern and it is enormously suggestive.
• There’s a combustion source running in an enclosed space. Heat beads, a brazier, a BBQ, a camp stove, an unflued gas heater, a generator, a car idling in a garage.

If you’re standing in a house that ticks two of those boxes, you have your answer. Act on it.

First Aid for Suspected Carbon Monoxide Poisoning

This is the part where good intentions kill people, so we’re going to be very direct about the order of operations.

Step 1: Do Not Become the Next Patient

Carbon monoxide does not care that you are the rescuer. If you walk into a room that has already dropped four adults, it will drop you too, and it will do it faster because you’ll be exerting yourself.

Note what the Mount Gambier firefighters did: they arrived, recognised a possible gas hazard, and initiated a HAZMAT response before entering. Professional responders with breathing apparatus treated that house as a threat. You have no breathing apparatus and no gas detector.

So: do not enter an enclosed space you believe contains carbon monoxide. If you can open external doors and windows from outside to ventilate the space, do it. If a person is close enough to the doorway to be pulled out quickly without you going deep into the space, and you can do it in seconds, do it. Otherwise, stay out and wait for the fire service. This feels wrong. It feels like cowardice. It is not — a second unconscious body in a toxic room makes the situation exponentially worse for everybody, including the person you were trying to save.

Step 2: Call Triple Zero (000)

Ask for Fire and Ambulance, and use the words: “I think there’s carbon monoxide in the house.” That single sentence changes everything on the other end. It tells the fire service to come with breathing apparatus and gas detection, and it tells the ambulance crew to arrive expecting a patient who needs high-flow oxygen.

For advice on a conscious person with milder symptoms, the NSW Poisons Information Centre is available around the clock on 13 11 26. But if anyone is drowsy, fainting, confused or unconscious, that’s a 000 call, not a phone-advice call.

Step 3: Fresh Air

Once the person is out of the contaminated space, get them into genuinely fresh air. Not “the next room”. Not “near a window”. Outside.

This is not just a comfort measure — it is the treatment. Removing them from the source is the single most effective thing you can do, and every minute of clean air starts to shift the balance back.

Step 4: Check for Response and Normal Breathing

From here, you’re on standard DRSABCD ground. Check for a response — talk to them, squeeze their shoulders. Open the airway. Look, listen and feel for normal breathing for up to ten seconds.

Be careful here. Agonal gasping — irregular, noisy, gulping breaths — is not normal breathing. It is a sign the brain is dying. People routinely mistake it for breathing and delay CPR because of it.

Step 5: If They’re Not Breathing Normally, Start CPR

30 compressions to 2 breaths. Push hard, push fast, in the centre of the chest, at least a third of the depth of the chest, around 100–120 compressions per minute. Attach a defibrillator the moment one arrives and follow the prompts.

Carbon monoxide patients in cardiac arrest are a hard save, and we’re not going to pretend otherwise. But their hearts have usually stopped because of oxygen starvation rather than underlying disease, and they are frequently younger and otherwise healthy — which is exactly the profile where good, early, uninterrupted CPR does the most work. Once they’re in fresh air and someone is pushing on their chest, you are buying time for paramedics with oxygen to arrive. That is a real, meaningful contribution.

If it’s been a while since you’ve practised this on a manikin, our CPR course exists for exactly that reason.

Step 6: If They’re Breathing but Not Fully Alert

Recovery position. On their side, airway open, head tilted so vomit can drain rather than pool — and carbon monoxide patients vomit a lot. Stay with them. Keep watching that they’re breathing normally, because a drowsy patient can deteriorate into an unconscious one while you’re busy feeling relieved.

Step 7: Everyone Gets Assessed. Everyone.

This one gets ignored constantly. The person who “feels fine” still needs to be seen. They were in the same air.

Carbon monoxide takes hours to clear from the blood on room air, and only a fraction of that time on high-flow oxygen — which is why paramedics carry it and why hospital assessment matters. Delayed neurological effects can appear days or even weeks later, including memory problems, personality changes and depression. And pregnant women need urgent assessment regardless of how well they feel, because a foetus is far more vulnerable to carbon monoxide than the mother is.

When paramedics arrive, they will want a history. This is where a structured handover earns its keep — if you know the SAMPLE acronym, use it, and lead with the exposure: what was burning, in what room, for how long, with what ventilation, and how many people were in the house.

The Things Not To Do

• Don’t go back in for something. Not the phone, not the dog, not the wallet.
• Don’t assume “it’s out” means “it’s safe”. Coals that have stopped flaming are still producing carbon monoxide. A “cooling” BBQ brought into a garage or a tent has killed people.
• Don’t rely on cherry-red skin as a sign. It’s the classic textbook cue, and it’s close to useless in the real world — it typically appears very late, often after death. If you’re waiting for it, you’ve waited too long.
• Don’t trust an open window. A cracked window does not make an enclosed space safe. Neither does an open garage door.
• Don’t put the person back inside to “warm them up”. Understandable instinct. Terrible plan.

Why This Matters on the Mid North Coast

Mount Gambier is a long way from Port Macquarie, but the conditions that produced this tragedy are not exotic.

Winter mornings here get properly cold, and plenty of homes across the Hastings and Manning are older, draughty, and heated with whatever’s to hand. Our region also runs on camping, caravanning and boating — three activities that generate carbon monoxide deaths every year in this country, because a tent, an annexe, a camper trailer and a boat cabin are all enclosed spaces, and every one of them is a place where somebody has, at some point, thought a portable BBQ or a camp stove would take the edge off the cold.

Then there’s the working end of things: generators, compressors, pressure washers and concrete saws running in sheds, garages and half-finished builds. Petrol engines are prolific carbon monoxide producers, and a shed with the roller door up is not the same thing as outdoors. SafeWork NSW treats carbon monoxide as a priority chemical for good reason, and notes that removing the worker from the contaminated atmosphere is what usually turns a poisoning into a full recovery.

And then there’s the honest structural point we keep coming back to on this blog: outside the main centres, help takes longer to arrive. In a metro suburb, a co-responding fire crew and an ambulance can be at the door in minutes. In Wauchope, Kempsey, Laurieton, or somewhere off the Comboyne road, the person standing in the driveway doing compressions may be doing them for a while. That’s not a criticism of our paramedics — it’s geography. It’s also the entire argument for having someone in every household who actually knows what to do.

Prevention: The Unglamorous List That Actually Works

The first aid industry has a habit of making everything into an acronym with a laminated poster. This one doesn’t need it. It’s four rules.

1. Nothing that burns fuel comes inside. Ever. Heat beads, charcoal, BBQs, braziers, hibachis, camp stoves, gas patio heaters, generators. Not in the house, not in the garage, not in the tent, not in the caravan, not in the car, not in the boat cabin. NSW Health is explicit: these items are for outdoor use only, and if you use them inside, carbon monoxide can build up to dangerous levels quickly.
2. “Nearly out” is still dangerous. The most dangerous coals are the ones that look harmless.
3. Get gas heaters serviced. Open-flued and unflued gas heaters have their own grim history in this country. A gas fitter’s inspection every couple of years is cheap.
4. Install a carbon monoxide alarm. Not a smoke alarm — a carbon monoxide alarm. They’re inexpensive, they’re widely available, and NSW Health recommends choosing one certified to the American standard UL2034 or the European standard EN50291, installed near bedrooms and rooms with gas heaters. If you have gas appliances, a fireplace, or an attached garage, this is one of the highest-value safety purchases in your house.

That’s it. That’s the whole prevention strategy. It’s not clever and it’s not interesting and it would have prevented the Mount Gambier deaths entirely.

Frequently Asked Questions

Can you smell carbon monoxide?

No. Carbon monoxide has no colour, no smell and no taste. You may smell other combustion products alongside it — smoke, fumes, exhaust — but the carbon monoxide itself is completely undetectable to human senses. This is why alarms exist.

How long do heat beads take to become dangerous indoors?

Dangerously high concentrations can build in a closed room within minutes to a couple of hours, depending on the size of the room, how many beads are burning, and how well sealed the space is. There is no safe duration and no safe quantity indoors. A single small barbecue can generate lethal levels in an average bedroom.

Are heat beads safe indoors if I open a window?

No. Ventilation reduces the rate of build-up; it does not eliminate it. Carbon monoxide accumulates faster than a cracked window can clear it, and people have died in rooms with open windows and in garages with the door up. The rule is not “ventilate well” — the rule is “not indoors”.

What are the first signs of carbon monoxide poisoning?

Headache, nausea, dizziness, weakness and confusion — symptoms that feel very much like the flu or a hangover. The strongest clue is usually context rather than symptoms: several people in the same building feeling unwell at once, symptoms that improve outside the house and return inside, or a combustion source running in an enclosed space.

Will my smoke alarm detect carbon monoxide?

No. Smoke alarms detect particles of smoke. Carbon monoxide is a gas, and a smouldering bed of coals or a faulty gas heater can produce lethal levels while making almost no smoke at all. You need a dedicated carbon monoxide alarm, and it needs to be a separate device.

Is it safe to use a BBQ in a garage with the door open?

No. A garage is an enclosed space regardless of whether the roller door is up. Carbon monoxide is heavier than you’d assume it behaves — it mixes and lingers rather than politely drifting out the opening. The same applies to carports, sheds, annexes and undercroft areas.

What’s the first aid treatment for carbon monoxide poisoning?

Fresh air is the treatment, and getting the person out of the contaminated environment safely is the priority. Then call 000, check for response and normal breathing, start CPR if they aren’t breathing normally, and place them in the recovery position if they are breathing but not fully alert. Every exposed person needs medical assessment, including anyone who feels fine.

Should I go in and rescue someone from a room with carbon monoxide?

Only if you can reach them and get out within seconds without entering deeply into the space. Carbon monoxide incapacitates rescuers quickly, and an unconscious rescuer makes the emergency far worse. Ventilate from outside if you can, call 000, and let the fire service enter with breathing apparatus.

Does a first aid course cover carbon monoxide poisoning?

Yes. HLTAID011 Provide First Aid covers scene safety and hazard assessment, the DRSABCD action plan, CPR and defibrillation, the recovery position, and the management of an unconscious casualty — which is exactly the skill set a carbon monoxide incident demands. It also covers respiratory emergencies and inhaled poisons more broadly.

Learn the Skills That Turn a Bystander Into a Responder

Four people in Mount Gambier went to sleep in a warm house. Three of them came out alive because somebody raised the alarm and trained responders knew exactly what they were walking into.

You can’t control whether an emergency happens. You can control whether you know what to do in the first ten minutes of one — and in regional NSW, those first ten minutes are often the whole ball game.

Enrol in a course — HLTAID011 Provide First Aid is $140, HLTAID009 Provide CPR is $59, and the blended format means a single two-hour practical session with your certificate issued the same day.

View upcoming course dates for our regular first aid courses in Port Macquarie and first aid training in Taree, with sessions running throughout the year across the Mid North Coast.

Need to train a team? If your staff work around generators, plant, gas appliances, confined spaces or vehicle exhaust, carbon monoxide is a live workplace hazard, not a theoretical one. We deliver workplace first aid training on site across Port Macquarie, Taree and the wider Mid North Coast — request a group booking and we’ll bring the training to you.