Topeka ? Federal officials said Friday that Kansas hasn’t imposed strict enough limits on the potential air pollution from a new coal-fired power plant in the southwest part of the state.

The U.S. Environmental Protection Agency questioned parts of a state Department of Health and Environment air-quality permit issued in December, which allowed construction of the plant by Sunflower Electric Power Corp. The utility, based in Hays, wants to build the plant next to an existing coal-fired plant outside Holcomb, in Finney County.

The EPA’s regional office in Kansas City, Mo., released a letter Friday from Administrator Karl Brooks to KDHE Secretary Robert Moser, seeking “dialogue” about the air-quality permit. The letter says the EPA finds the permit’s limits on emissions of nitrogen oxides and sulfur dioxide too lax.

EPA spokesman David Bryan said the state and the federal agency appear to disagree over whether Sunflower’s permit must be in line with tougher emissions rules issued by EPA last year. The federal agency wants Kansas to impose per-hour limits on the two pollutants, rather than 30-day averages.

In a separate statement, the EPA’s regional office said short-term exposure to the two pollutants can cause people to have difficulty breathing and increase symptoms of asthma, resulting in more hospital visits and respiratory illnesses.

“All we want to do is sit down with KDHE and go over those parts of the permit and get some answers,” Bryan said during an interview.

It’s not clear yet what the letter means for Sunflower’s $2.8 billion project, which has bipartisan support among state legislators and the strong backing of Republican Gov. Sam Brownback. Bryan said the EPA isn’t stepping in to halt the project, and he wouldn’t speculate about where talks with state officials could lead.

Sunflower spokeswoman Cindy Hertel said the company won’t comment until next week about the EPA letter because, “We are still reviewing it.”

KDHE officials also were reviewing the letter before responding. The permit was issued by Moser’s predecessor, Acting Secretary John Mitchell, who remains the director of the department’s Division of Environment. At the time, Mitchell said of EPA officials, “I will be very surprised if they have any problem with what we have done.”

Brooks’ letter said the state agency “has not adequately addressed” concerns about proposed limits on pollution raised by EPA in August. At the time, KDHE was considering a draft of the air-quality permit that Mitchell eventually issued.

Environmentalists strongly oppose Sunflower’s project, and the Sierra Club has asked the state Court of Appeals to overturn the air-quality permit. The environmental group raises the permit’s provisions on nitrogen oxides and sulfur dioxides as an issue, among others.

Amanda Goodin, an attorney for the environmental group Earthjustice, who’s involved in the case, saw the EPA letter as a warning to Moser and other state officials. She described it as the first step in a review that eventually could lead federal officials to block Sunflower’s project.

“This EPA letter points out one of the most obvious failings of the permit,” she said. “I think Kansas is just looking for a way to make this permit more lax.”

Sunflower supplies power for about 400,000 Kansans and plans to build a plant with a capacity of 895 megawatts, enough to meet the peak demands of 448,000 households, according to one state estimate. Three-quarters of the new capacity, or 695 megawatts, would be reserved for a Sunflower partner, Tri-State Generation and Transmission Association Inc., of Westminster, Colo.

That’s long been a sore point for many critics of Sunflower’s push to add coal-fired generating capacity, but the utility’s supporters say exporting electricity is as beneficial as exporting beef, wheat and other agricultural commodities.