The Allegheny County Health Department has approved an installation permit for the first phase of U.S. Steel Corp.'s planned $1 billion coke oven replacement and upgrade project in Clairton.

The permit, issued late Thursday afternoon following a 45-day public comment period, allows U.S. Steel to replace three of its 12 coke batteries -- Batteries 7, 8 and 9 built in 1954 -- with a single battery, Battery C, that would have fewer but bigger ovens and equal production capacity.

The company plans to begin construction immediately after a 10-day appeal period ends, and the new battery is scheduled to be operational by December 2011.

In issuing the permit, the health department lowered emissions limits and added more testing requirements for the company. Jim Thompson, director of the department's air quality program, said the added testing will ensure that U.S. Steel keeps the new coke ovens and pollution controls operating at high levels.

"We're pleased with the permit and we believe the emissions reductions and best available pollution controls will be a positive step in improving air quality," said John Armstrong, a U.S. Steel spokesman.

But a coalition of environmental groups continued to criticize the project for not doing enough to clean up the chronic soot pollution problems in the Clairton-Liberty area where about 25,000 people live. The area, which also includes Glassport, Lincoln and Port Vue, is classified as a "non-attainment area" by the U.S. Environmental Protection Agency because it does not meet national health standards for fine particle emissions.

Kathy Lawson, Western Pennsylvania director for Clean Water Action, commended the health department for strengthening parts of the permit but said the final permit does not reduce overall emissions limits so "it's impossible to quantify whether or not the revisions will have any effect."

She said the environmental groups have not yet decided if they will appeal the permit approval.

The coke works, the largest in the U.S., is located on 392 acres along the west bank of the Monongahela River in Clairton.

After the Battery C work is finished, the company will replace Batteries 1, 2 and 3, built in 1955, with a new Battery D, identical to Battery C. Plans are to finish that work by 2013. A second installation permit will be required for the work. Maintenance work and upgrading of other coke batteries will also be done, but that work does not require a county permit.

Coke is a solid carbon fuel and carbon source produced by baking coal and is used to melt and reduce iron ore in the steelmaking process. Making coke is a dirty process that produces airborne emissions of gases and particles from the brick-lined ovens and when the hot, baked coke is "pushed" out of the ovens and "quenched" or cooled with water.

U.S. Steel has said the project will include state-of-the-art pollution controls and estimated that replacement of the first three old batteries with Battery C will reduce all air pollution emissions by 39 percent and soot emissions by almost 58 percent.

According to the health department, soot emissions from batteries 7, 8 and 9 now total 751 tons a year, and will be reduced by 383 tons to 368 tons from Battery C.

Although health department Executive Director Bruce Dixon said the replacements and improvements at the coke works will "dramatically improve air quality and help bring the Liberty/Clairton area into attainment," Mr. Thompson said the changes at the coke works by themselves won't be enough to bring the Mon Valley communities into attainment of the federal health standards.

"Because 70 percent of our pollution in Allegheny County is transported here from upwind sources, there will need to be improvements in those areas to bring us into attainment," he said.

Dee Kruse, a Clairton resident and member of Residents for a Clean & Healthy Mon Valley, acknowledged that the project is an important one for the environment and economy of the Mon Valley but said it must be done right to protect the health of residents.

"The health department rushed this permit through for U.S. Steel's convenience, but it didn't take the time to strengthen the emission limits and help guarantee that our air can meet federal standards in the future."