Natural gas stoves – a heated health topic
by Adam Grossman & Sheryll Mangahas
A commissioner from the US Consumer Product Safety Commission (CPSC) recently gave an interview to Bloomberg News suggesting that gas stoves are a “hidden hazard” and that his agency could consider banning the type of stove used in approximately 40% of American households. As this tidbit of news went viral and became politically divisive, many were left wondering why the government would be interested in banning these popular appliances.
Gas stoves, seemingly innocuous appliances, generate their heat by burning natural gas – primarily methane with a few other lightweight hydrocarbons and mercaptan (the distinctive smell) mixed in. While theoretically the only products of that combustion are carbon dioxide and water, we now know that it’s not that simple. Burning natural gas actually produces nitrogen oxides, carbon monoxide, and particulate matter.
Scientists have researched the potential health effects of all these compounds and the findings are not good. Nitrogen dioxide (NO2) reduces lung function, especially in children. Carbon monoxide (CO) and NO2 are both associated with heart failure. Particulate matter is strongly associated with cardiovascular events like heart attack and stroke. The scientific evidence that these chemicals can cause harm is strong enough that CO, NO2, and particulate matter are regulated in outdoor air under the Clean Air Act and are known as “criteria air pollutants”, which are those pollutants controlled most strongly by the EPA. The EPA is required to set National Ambient Air Quality Standards (NAAQS) for the criteria air pollutants based on periodic review of the latest scientific data. Perhaps surprisingly, there are no equivalent standards at the federal level for indoor air.
But why is there so much attention on gas stoves compared to the other three commonly used gas-burning appliances: furnaces, water heaters, and clothes dryers? We all know that the venting on gas stoves is rather hit-and-miss, with some installations having high quality exhaust fans while others have little to no exhaust. Unlike gas stoves, though, the other three types of gas appliances all have mandated exhaust systems and must vent their combustion gasses outdoors rather than indoors. That means gas stoves are uniquely positioned to pollute the air inside our homes.
The health risk from poorly ventilated gas stoves in our homes is only one part of the risk; gas stoves also contribute to climate change in three different ways. First, and most obviously, burning hydrocarbons releases carbon dioxide directly into the atmosphere, contributing to global warming. Even if the scale of one’s cooking is significantly smaller than the CO2 emitted by, e.g., driving, the large number of gas stoves in homes and commercial kitchens contributes significantly to the overall problem of climate change. Second, gas stoves leak methane even when they are not in use. Methane is a much more potent greenhouse gas than carbon dioxide, contributing 84 times the global warming potential of carbon dioxide over 20 years. Third, the entire natural gas pipeline from extraction and transport to its final destination leaks methane into the environment. Studies have attempted to determine how much methane is lost in transit, and some have determined that the gas infrastructure in our largest cities releases close to a megaton of methane per year.
With the consequences of our using natural gas in our homes becoming clearer, it’s fair to wonder whether liability will emerge and what it might look like. As with many hazards with ubiquitous human exposure, it will be difficult for individual plaintiffs to prove in court that, for example, their asthma was caused by the natural gas stove in their house. That doesn’t mean that individual plaintiffs won’t try, but it also makes it potentially more attractive for state attorneys general to seek damages from the natural gas and appliance industries for the overall health burden their products have brought to society. Attribution science may provide the needed link – if scientists estimate that 12% of childhood asthma is caused by gas stoves, then the state can argue the companies should pay 12% of the cost to treat it. One estimate puts the annual cost at $5.9 billion with per child costs going as high as $13,600.