An Oct. 29 article incorrectly described the reason energy companies have decided in recent years to build coal-fired plants instead of natural gas plants. The reference should have been to natural gas prices, not gasoline prices. (Published 10/30/04)

In the last four years, power companies have deluged regulators with applications to build power plants in locations that could affect air quality and visibility in national parks or wilderness areas, according to federal statistics compiled by the Natural Resources News Service, a nonpartisan organization.

Since 2000, the number of permits sought for plants within 62 miles of park boundaries has quadrupled, compared with the previous five years, and 33 of the 280 proposed plants would be coal-fired. Both trends have prompted concern among federal and state officials that the energy boom could harm already reduced visibility.

Between 1995 and 1999 utilities built 10 coal plants nationwide, none within that distance of a national park or wilderness.

The trend is particularly pronounced near some popular tourist sites in the West, where National Park Service and state officials say visibility-obscuring haze is increasing.

Several recent studies indicate that while visibility is improving in many parks on the East and West coasts, the overall number of low-visibility days is on the rise. A federal report found that as of 1999, on the 20 percent of days when skies are haziest, "most parks show at least some degradation or worsening of conditions, especially in the Southwestern U.S.," compared with 1990. A Park Service report last year concluded that "poor air quality currently impairs visibility in every national park and most, if not all, wilderness areas."

"The interior West is witnessing the biggest resurgence in coal-fired power plants in a generation," said Vickie Patton, a senior attorney for the advocacy group Environmental Defense, "and these power plants will release air pollution that threatens human health, mars scenic vistas in premier national parks and adds staggering amounts of climate-disturbing greenhouse gases to the atmosphere."

Interior Department officials, however, said they have been working with utilities and state agencies to ensure that energy development will not harm the environment.

"We can have our power and clean air, too," said Paul Hoffman, deputy assistant secretary for fish and wildlife and parks. "It is not our job to stop power plants; it's to ensure if they're built, they don't have adverse impacts" on parks and wilderness areas.

New power plants tend to be cleaner than older ones, and Hoffman said this would help improve park visibility in the long run.

But several state and federal officials said in interviews that the increase in power production would exacerbate existing visibility problems stemming from wildfires, dust, weather and industry.

"We do continue to see a deterioration in visibility in the Southwest and Intermountain West area," said Chris Shaver, who directs the Park Service's air quality division. "It also seems to be a hot spot for energy development. There's reason to be concerned."

While most utilities focused in the 1990s on building natural gas-powered plants, rising gasoline prices have prompted some to shift new plants to coal, which produces much more pollution.

Outside Colorado's Mesa Verde National Park, home to ancient Anazasi cliff dwellings, there are three pending power plant applications as well as a plan to drill 10,000 gas wells over the next 20 years, said George San Miguel, the park's natural resource manager.

"If all these things happen, Mesa Verde could be negatively impacted," San Miguel said.

Although the states issue the permits in most cases, the federal Clean Air Act requires park officials to review any proposed plant that could affect a park larger than 5,000 acres or a wilderness area of more than 6,000 acres. Park officials negotiate with utilities if a project could measurably diminish visibility, but park officials said nearly all permits get approved.

Park officials, Shaver said, have to rely on "friendly persuasion," which produces mixed results. This month, the Utah Department of Environmental Quality signed off on a proposed Intermountain Power Project Corp. (IPP) plant despite warnings that it could worsen declining visibility at Capitol Reef National Park. On May 27, Hoffman told Utah regulators that the plant on its own would not harm park views, but "emissions from the existing IPP boilers could be diminishing visibility at the potentially affected . . . areas that we manage, and adding the proposed new unit could further contribute to this visibility degradation."

Scott Segal, who represents utilities as director of the Electric Reliability Coordinating Council, said the Bush administration is addressing critics' concerns by pushing for new air pollution rules that would reduce sulfur dioxide, nitrogen oxide and mercury emissions over the next 14 years.

Emissions from power plants in proximity to parks and wilderness sites may be a factor in haze accumulating over such areas as the Great Smoky Mountains National Park.