Carbon monoxide is the travel risk almost nobody plans for. The gas is odourless and colourless, it leaks from fuel-burning appliances like heaters, fireplaces and water heaters, and its symptoms — headache, nausea, dizziness, fatigue — get mistaken for flu or food poisoning. Anyone affected while asleep may never notice anything at all.
Chuck Heathco has reason to warn people. His son Johnny and Johnny's girlfriend died of acute carbon monoxide poisoning in 2023 at a luxury resort in Mexico. Since then, more families have lost loved ones: a 14-year-old boy at a Costa Rican resort in 2025, and three American tourists killed at a Belize hotel with a faulty water heater the same year. Heathco now runs the John Wesley Heathco Legacy Foundation to raise awareness and push for policy change.
The regulatory gap is bigger than most travellers assume. Only 14 US states require carbon monoxide alarms in hotels and holiday rentals — the other 36 don't. Overseas it's often worse: the US Embassy in Costa Rica notes that most Latin American countries have no widespread detector mandates. And even where detectors exist, there's no guarantee they're tested or working.
The fix is cheap and light. A battery-powered portable detector takes up about as much room in your bag as a smartphone. Buy one that meets Underwriters Laboratory (UL) standards, running on batteries or plug-in power with battery backup. Heathco's habit: keep it in a plastic bag in your suitcase permanently, so it's always ready for the next trip.
Once you arrive, place the detector near your sleeping area — not by the floor, since CO is slightly lighter than air and diffuses evenly through a room. Keep it away from vents, windows and fireplaces. Test it regularly, swap the batteries as needed, and replace the unit every five to ten years.
If the alarm sounds, leave the building immediately and tell hotel management. Call 911 or the local emergency number — your room may not be the only one affected, and acute exposure can impair you within minutes. If you ever feel flu-like symptoms indoors, remember the acronym HEADS UP: headache, exhaustion, aching muscles, dizziness, sick stomach, unclear thinking, pale skin. Get to fresh air; if CO is the cause, symptoms fade quickly since the gas leaves your system in roughly five hours. And remember the risk isn't limited to bedrooms — restaurants, hotel lobbies and even open-air boats can be affected.
Worth calling your accommodation before you book, too: ask whether detectors are installed in rooms and common areas, how often they're tested, and search for any past CO incidents at the property. If answers are vague, pack your own device without hesitation.
This is a story every traveller should read, whether you're booking a beach resort or a city apartment. Detectors cost relatively little, fit anywhere, and — as Heathco puts it — you just stick the alarm in your suitcase. It's the simplest safety upgrade you can make this year.