PITTSBURGH — Seven Northeastern and mid-Atlantic states announced plans Tuesday to sue the Environmental Protection Agency, saying it is violating the Clean Air Act by failing to address methane emissions from oil and gas drilling, which has boomed in nearby states such as Pennsylvania and West Virginia.

New York Attorney General Eric T. Schneiderman said in a news release Tuesday that the EPA is violating the Clean Air Act by failing to address the emissions. Methane is a potent greenhouse gas, and the oil and gas industry is the largest source of emissions in this country. Other major sources come from landfills and livestock.

The EPA said in an email that it plans to review and respond to the notice from the states.

Howard Feldman, a spokes-man for the American Petroleum Institute, said the lawsuit “makes no sense” since the EPA passed rules on oil and gas emissions earlier this year, and many companies have already started installing new equipment to limit methane leaks and other pollution. Those rules take effect in 2015.

Peter ZalZal, a staff attorney with the Environmental Defense Fund, said the group thinks the recent EPA rules are “a good first step,” but that more can be done to target methane emissions directly.

“We think that controlling and reducing methane emissions from the oil and gas industry is critical,” ZalZal said.

Schneiderman said that the coalition of states “can’t continue to ignore the evidence of climate change or the catastrophic threat that unabated greenhouse gas pollution poses to our families, our communities and our economy.” He said Connecticut, Delaware, Maryland, Massachusetts, Rhode Island and Vermont joined in sending a required 60-day notice of intent to sue to EPA.

Pennsylvania, West Virginia  and Ohio — all states with intensive oil and gas drilling — didn’t join in the campaign. None of the states that sent the notice to the EPA are major producers of oil or gas.

It’s not clear whether New York is also taking extra steps to limit methane emissions from other sources. While the EPA estimates that the oil and gas industry is responsible for 37 percent of the nation’s methane emissions, landfills are responsible for 16 percent, and livestock such as cattle and pigs contribute 21 percent. Some natural gas leaks also occur not just at wells, but from distribution networks in cities.

Many experts have noted that addressing the methane problem can even make financial sense for the industry, because by reducing leaks they end up with more product to sell.

Overall, the EPA says that methane is responsible for 3.8 percent of the total greenhouse gas emissions in the United States. Other major greenhouse gases are carbon dioxide, nitrous oxide and ozone. Methane is a more potent greenhouse gas than carbon dioxide, but it also decays much quicker.

Patrick Henderson, Pennsylvania’s energy executive in Gov. Tom Corbett’s office, noted that other top New York officials have recently supported more natural gas use.

“Gov. Cuomo proposed investing $500 million in natural gas distribution infrastructure, and New York City Mayor Bloomberg wrote in a Washington Post op-ed that shale gas ‘is one of the best things we can do to improve air quality and fight climate change,”’ Henderson said in an email.

Henderson added that natural gas also has environmental benefits, since it emits just 50 percent of the carbon dioxide of coal-fired power plants. That switch from coal to gas has contributed to declining greenhouse gas emissions in the U.S., according to federal energy statistics. He also noted that increased domestic oil and gas production has helped reduce imports.

Federal climate researchers say they haven’t yet seen signs that increased drilling is affecting global methane levels, but they’re worried about the threat.

“Not the mid-latitudes where the drilling is being done, which is interesting,” said James Butler, head of global monitoring for NOAA. Butler said the tropics and the arctic are the biggest current sources, from decaying vegetation (linked to a rise in rainfall) and thawing of the Arctic tundra (linked to global warming).