SHERIDAN, Wyo. (AP) — A federal restriction imposed on Sheridan in northern Wyoming in the late 1980s has been lifted as the result of decades-long efforts to improve air quality in the city.

The Environmental Protection Agency officially recognized Sheridan as an area in attainment with federal air quality standards earlier this month. The action lifts a construction ban on projects that could lead to air pollution and acknowledges that pollution control efforts have been effective.

"What it does is, it makes it easier for other industries to come into Sheridan because their regulations that will be less restrictive," city public works director Lane Thompson said. "But the big thing is, we have cleaner air for our residents to breathe."

Keith Guille, a spokesman for the Wyoming Department of Environmental Quality, said the re-designation is a formal recognition that Sheridan has been in compliance with federal air quality standards for several years.

Mike Morris, member of the DEQ's air quality division, said Sheridan had noticeable air quality issues in the early 1980s, particularly in the winter and spring, caused by dust kicked up on roads.

"Some of our documentation, historically, showed there was visible pollution," Morris said. "It looked like there was sort of a dust in the air."

Sheridan was designated as an area in nonattainment in 1987. As a result of that designation, the state placed a construction ban on sources of dust pollution.

Though he could not point to a construction project that was limited by that ban, Morris used big industrial facilities as an example of the type of projects that could have been restricted.

To restore the city's air quality, Sheridan partnered with the DEQ to come up with, and implement, a pollution control plan. Part of that plan required the city to overhaul its road maintenance plan.

Morris noted that air quality in the city has improved steadily since new standards were implemented in the early 1990s.

Guille said Sheridan's re-designation is part of a wider effort to ensure the entire state is complying with federal air quality standards. The Upper Green River Basin is the only area in the state still designated as nonattainment, but Guille noted the area has been meeting federal standards for several years.