WASHINGTON – Air pollution from thousands of natural gas wells that are “fracked” every year will be reduced under regulations that the Environmental Protection Agency issued Wednesday.

It’s the first time the EPA has required air pollution controls at hydraulically fractured, or fracked, wells. The new rule targets smog-forming volatile organic compounds and air toxics that increase cancer risks. The same equipment also would trap methane, a potent heat-trapping gas in the atmosphere.

President Obama has called for expansion of natural gas production with fracking, but he has said it should be done without harming health and safety. While water pollution has gotten most of the attention, natural gas production, processing and delivery also produce large amounts of air pollution.

The rule mainly would require companies to capture the burst of emissions that occurs as a well is being prepared for commercial production.

Beginning in 2015, all fracked wells will be required to use “green completions.” The process involves truck-mounted equipment that captures the waste that flows for about three to 10 days after water, sand and chemicals are injected into a well. The captured gas and liquid hydrocarbons can be separated, treated and sold.

Fort Worth, Texas, and other cities already require green completions, as do Colorado and Wyoming. The EPA estimates the equipment is used voluntarily in 50 percent of wells today.

“This levels the playing field,” said EPA air administrator Gina McCarthy. She said the rule was designed to promote responsible production of natural gas and to protect the public, and it will “do it in a way that more than pays for itself.”

The American Petroleum Institute, the industry’s lobby group, had argued that the EPA underestimated the cost of the equipment and had asked for an exemption for many wells. The EPA didn’t grant that exemption but accepted the industry’s request for more time to build the equipment needed for green completions.

The institute had no comment about costs because it needed to review the details, said spokesman Carlton Carroll. “We were pleased that they recognized the need for a phase-in period.”

But the Western Energy Alliance, another trade group, said in a statement that the EPA overestimated the benefits and underestimated the costs of compliance. It said the rule would result in minimal environmental benefit and higher energy costs.

Environmental groups said the benefits were broad.

“These important rules start to cut down on air pollution that harms people living near wells, creates smog and warms the climate,” David McCabe, senior scientist with Clean Air Task Force, said in a statement. “They are a solid start, but we need to keep working to reduce pollution from the gas industry all the way from the well to the customer. People who live near compressors and equipment already in use need to see their air cleaned up as well. Unfortunately, these rules won’t do that.”