A consumer watchdog group is suing a manufacturer of gas stoves for allegedly failing to warn people that its appliances can produce harmful air pollution.

On Thursday, the United States Public Interest Research Group Education Fund sued a company called Haier U.S. Appliance Solutions in the District of Columbia Superior Court. It says the manufacturer is violating a consumer protection law in Washington, D.C., that prohibits “deceptive and unconscionable business practices.” Haier bought General Electric’s GE Appliances business in 2016.

The burners on gas stoves release pollutants including nitrogen dioxide, a key element in smog that can irritate airways and may contribute to the development of asthma, according to the U.S. Environmental Protection Agency.