When heaters kill

Pushpa Girimaji

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I was most distressed to read about the death of eight Indians on a holiday in Nepal. From what I could make out of the newspaper reports, these persons died of asphyxiation caused on account of a gas-based room heater they were using in their hotel. This has got me worried because in severe winter months, we too use room heaters that work on gas, particularly when I go to my parents’ home in Himachal Pradesh. Heavy snowfall disrupts power for days. So can you please explain how safe or unsafe these room heaters are and why do they become so dangerous?

I am really glad you asked this question because it is absolutely imperative that consumers be aware of the risks involved in using gas-based heaters. In this case, from what I can make out from the news reports on the tragedy, the eight tourists from Kerala checked into the hotel late in the night and, as it was extremely cold, asked for a room heater. They were reportedly given an eight-foot outdoor gas heater, which should never have been used indoors. To make matters worse, eight of them slept in one room to get the warmth from the lone heater and shut the door and the windows to keep out the cold air while they slept. That was a sure invitation to disaster.

Like all combustion products, unvented portable room heaters that work on gas, wood, kerosene or coal should never be used in enclosed spaces with no ventilation. Unfortunately, there is very little consumer awareness about this.

Now let me explain why these gas heaters are risky. First and foremost, they must be built according to stringent quality standards so that when the gas burns, there is complete and efficient burning of the fuel. When this happens, each carbon atom in the fuel binds with two atoms of oxygen in the air and releases carbon dioxide. However, if the quality of the room heater is not good, it can well lead to incomplete combustion of the fuel. When that happens, the carbon atom binds with only one oxygen atom, releasing carbon monoxide.

That’s not all. Even if the room heater is of good quality, it needs sufficient oxygen to burn efficiently. If, for example, it is placed in a room with all windows and doors shut, the gas first uses the oxygen in the room to burn completely. But with no fresh air coming in, slowly, the oxygen level in the room depletes, leading to incomplete combustion, thereby releasing carbon monoxide. If there is no outlet for the toxic air to escape, it builds up to an alarming extent inside the bedroom. And in most such cases, people who are sleeping and breathing that air will become unconscious and die.

Carbon monoxide is known as a silent killer because it takes the victim unawares. It has no smell or taste, nor is it an irritant to the eye or nose or skin. So, it is very difficult to detect it, except with a carbon sensor. The haemoglobin in our blood, which carries oxygen to the various cells, tissues and organs, has great affinity for carbon monoxide and as the concentration of CO in the air increases, it displaces the oxygen in the heamoglobin. And without oxygen supply, the cells and tissues in the body begin to die.

At low levels, CO inhalation causes dizziness, nausea, headache, vomiting, confusion, shortness of breath, but at higher levels, it causes disorientation, impairs your thinking, muscle coordination, thereby preventing you from escaping from the polluted area.

Precautions to take

Go in for a good quality, third-party certified electric room heater. If you are forced to buy a gas-based heater, buy a third-party guaranteed, quality room heater for indoor use, with an oxygen depletion sensor. The sensor should cut off supply to the heater if the level of oxygen in the room goes below 19.5 per cent. In normal air, the concentration of oxygen is 20.95 per cent. And wherever you use it, you should also have a carbon monoxide alarm. However, these alarms shouldn’t make you complacent. Ensure good ventilation in the room. Never go to sleep with the heater on.