BANGKOK — January 7, 2026, Nopparat Rajathanee Hospital, under Thailand’s Department of Medical Services at the Ministry of Public Health, has issued a warning about the dangers of water heaters, saying the most serious threat is carbon monoxide poisoning, which is commonly linked to gas-powered water heaters that are improperly installed or used in poorly ventilated spaces.
The hospital said that in early 2026 there were reports of a family narrowly escaping death after inhaling toxic gas while showering at a resort in a cold-climate area.
Dr Akkharat Jitnuyanont, deputy director-general of the Department of Medical Services, said gas water heaters rely on combustion to heat water. If combustion is incomplete, carbon monoxide can be produced. Inhalation of the gas prevents oxygen from being properly used by the body, leading to oxygen deprivation.
Symptoms can include headaches, dizziness, fainting, difficulty breathing, loss of consciousness and abnormal heart rhythms, which can ultimately be fatal, he said.
“In addition, propane gas, which is used as cooking gas and sometimes to heat water, may leak and displace oxygen in the air. When inhaled, it can cause headaches, nausea, vomiting, dizziness and loss of consciousness,” Dr Akkharat said.
He advised that when using gas water heaters, exhaust fans should always be switched on during use. Users should avoid showering continuously for long periods and should take breaks, opening doors and windows to improve ventilation. If symptoms such as fainting, nausea or vomiting occur, the affected person should be moved immediately to a well-ventilated area. If the person loses consciousness, help should be sought immediately and emergency services contacted by calling the 1669 hotline.
Dr Piyawat Laohutanont, director of Nopparat Rajathanee Hospital, said substandard gas water heaters pose a serious risk because incomplete combustion can generate high levels of carbon monoxide (CO), a colourless and odourless gas. Inhaling CO reduces the ability of red blood cells to carry oxygen, leading to oxygen deprivation, loss of consciousness and death.
He added that electric water heaters also carry risks, particularly from electric leakage, if proper grounding or effective earth leakage circuit breakers (ELCBs) are not installed.
Consumers planning to buy a new water heater, or those already using one, are urged to have safety checks carried out regularly. Further information is available from the Toxicology Centre at Nopparat Rajathanee Hospital on 02-517-1000 ext 5713.