OAKLAND, Calif.— The Center for Biological Diversity and Sierra Club filed a lawsuit today challenging the Environmental Protection Agency’s failure to ensure that areas in nine states and two U.S. territories have effective plans for cleaning up sulfur dioxide air pollution.

More than 1.6 million people live in these areas, which have sulfur dioxide pollution high enough to harm human health and the environment.

“The EPA’s completely unnecessary delay in taking real action on this harmful air pollution is endangering the health of hundreds of thousands of people,” said Ryan Maher, an attorney at the Center for Biological Diversity. “These delays amount to illegal subsidies for fossil fuels, slowing our transition to a clean energy economy.”

The Clean Air Act requires the EPA to set national ambient air quality standards to protect people and the environment from pollutants like sulfur oxides. When those standards are violated, the agency must ensure that states have valid plans in place to clean up the pollution.

“The diverse health harms from this pollution include the worst possible consequences,” said Zachary Fabish, a Sierra Club attorney. “It’s imperative that the EPA uphold its duty to protect the public’s health by acting immediately, as the law requires.”

The largest source of sulfur air pollution is the combustion of fossil fuels by power plants. Sulfur dioxide is also produced during industrial processes, such as extracting metal from ore and oil refining, and by ships, vehicles and heavy equipment that burn fossil fuels.

Some of the primary sulfur dioxide sources at issue in today’s notice include Arizona’s two copper smelters; coal-fired power plants in Tennessee and Texas; and chemical plants in Indiana and Louisiana.

Other areas suffering from air pollution covered by today’s notice are located in Guam, Illinois, Maryland, Michigan, Puerto Rico and Virginia.

Pollution associated with sulfur dioxide causes a range of public health and environmental problems. According to the EPA, exposure to sulfur dioxide air pollution can harm a person’s health in as little as five minutes, triggering asthma attacks and harm to the lungs and cardiovascular system that can be fatal.

Sulfur dioxide also contributes to acid rain and haze, damaging lakes, streams and ecosystems throughout the United States and decreasing visibility in national parks.

Today’s lawsuit is part of the two groups’ ongoing work to compel the EPA to protect human health and the environment from sulfur dioxide pollution in accordance with the Clean Air Act’s requirements.

More information about the fight against air pollution is available at Protecting Air Quality Under the Clean Air Act.