From Charleston Gazette:

Dozens of coal-fired power plants across the country lack the most modern pollution controls to limit air emissions linked to respiratory diseases and premature deaths, according to a report issued Friday by the U.S. Government Accountability Office.

Most of those plants instead built taller smokestacks, in an effort to disperse their emissions over a broader area — a practice that Congress tried to largely discourage when it amended the Clean Air Act more than 30 years ago, according to the GAO report.

The GAO review, requested by a Senate subcommittee, focused on issues concerning the use by utilities of taller smokestacks at coal-fired power plants.

Tall stacks can be used to help disperse sulfur dioxides, nitrogen oxides and other pollutants and limit air quality impacts in communities where power plants are located. But, they can also increase the distance that pollutants travel, harming air quality in downwind communities.

In 1977, Congress sought to encourage the use of pollution control equipment over tall-stack dispersion techniques to meet national air quality standards. The law does not limit stack height, but prohibits sources of emissions from using stacks taller than those considered “good engineering practice” to meet emissions limits.

Lawmakers interested in follow-up on the issue asked the GAO to report on the number and location of tall stacks of 500 feet or higher, the contribution of those plants to regional pollution problems, and the number of stacks built above the “good engineering practice” height.

Using Department of Energy data, GAO investigators found 284 “tall smokestacks” operating at 172 coal-fired power plants in 34 states as of Dec. 31, 2010. Of those stacks, 207 are 500 to 699 feet tall, 63 are 700 to 999 feet tall, and the remaining 14 are 1,000 feet or taller.

About one-third of these stacks are concentrated in five states along the Ohio River Valley, including 12 in West Virginia at power plants with a generating capacity totaling nearly 14,000 megawatts. The report did not list the individual plants.

“While about half of tall stacks began operating more than 30 years ago, there has been an increase in the number of tall stacks that began operating in the last 4 years, which air and utility officials attributed to the need for new stacks when plants installed pollution control equipment,” the GAO report said.