U.S. Steel Corp. has agreed to build two additional low-emission quench towers and install better pollution controls on old Batteries 1, 2 and 3, previously scheduled for demolition, as part of an ongoing upgrade of its coke works in Clairton.
The changes in U.S. Steel's coke works construction plans are expected to reduce the operation's small particle soot emissions by an additional 320 tons a year and allow Allegheny County to meet federal air quality standards by December 2013, almost two years earlier than previously expected, according to Allegheny County Health Department Director Bruce Dixon.
The construction plan changes included a memorandum of understanding signed Tuesday by the Health Department. When finalized it will amend a 2008 consent order and agreements between the county and company that required the steelmaker to shut down six of its 12 coke batteries in Clairton by 2013. The company also planned to make improvements to other batteries and build one new low-emissions quench tower.
The Health Department said the additional emissions reductions will be achieved by building the two new quench towers and bringing Batteries 1, 2 and 3 -- built in 1955 -- into compliance with air quality standards.
"We agreed to allow them to operate Batteries 1, 2 and 3 as long as they're brought into compliance, and we expect them to be in compliance," said Guillermo Cole, a Health Department spokesman.
Erin DiPietro, a U.S. Steel spokeswoman, declined to elaborate on the construction changes, say how much the new quench towers will cost or say whether the company still plans to build Battery D, another new coke battery that was part of the original plans announced in June 2008.
She said the revised plans now include a total of three new low-emission quench towers. Two older quench towers will remain in operation.
The company originally put a $1.2 billion price tag on the project. It already has permanently shut down Batteries 7, 8 and 9 -- built in 1954 -- and started construction of Battery C, which will have fewer but bigger coke ovens and equal production capacity.
Coke is a fuel and additive used in making steel. It is produced by baking coal in large brick-lined ovens without oxygen to remove impurities. The process produces airborne pollutants and particulates when gases leak from the ovens, when the hot coke is "pushed" out of the ovens and when the coke is cooled, or "quenched," with water.
The quenching occurs inside the quench towers, which are supposed to collect the steam and gases and particles that come off the coke as it is rapidly cooled. The new quench towers will allow about one-third of the emissions of the old ones.
Environmental groups had criticized the company's original plans and also the Health Department for approving them, because the 39 percent emissions reductions in the original plan, while substantial, were not enough to bring the Liberty-Clairton area into attainment of National Ambient Air Quality Standards for the tiniest airborne particles.
Higher concentrations of the airborne particles -- known as PM2.5 because they are smaller than 2.5 micrometers -- can be unhealthy. Studies have shown they can be breathed deeply into the lungs and aggravate a variety of health problems, including asthma, and also heart and lung diseases.
Joe Osborne, an attorney for the Group Against Smog and Pollution, said the old quench towers were the biggest sources of PM2.5 emissions, so replacing them with newer models "could be a positive."
The Liberty-Clairton area has been out of attainment since 1995 for the federal standards. A county plan submitted to the state Department of Environmental Protection in March of this year failed to reduce pollution below the federal health standard for Lincoln, part of that area.
"This is a better plan in terms of emissions reductions and air quality improvements and will reduce PM levels well below the standard," Mr. Cole said. "We think Lincoln will most likely meet the air quality standard."
Don Hopey: email@example.com or 412-263-1983.