PITTSBURGH A federal judge says an age discrimination lawsuit against PPG Industries Inc. can move forward as a class action.

U.S. District Judge Arthur Schwab says PPG must produce a list by April 13 of salaried employees who were at least 40 when they lost jobs in 2006 as the Pittsburgh-based paint, glass and chemical company downsized certain divisions.

Five former workers who were at least 52 sued PPG in 2007, saying older workers were fired or pressured to retire because management considered them a financial drain.

PPG has denied wrongdoing and says it doesn't discriminate or make employment decisions based on pension funding, as the plaintiffs claim.

Schwab's decision Wednesday clears the way for similarly situated workers to join the lawsuit.

CLAIRTON United States Steel Corp.'s $1.1 billion plan to cut pollution at a Pittsburgh-area coke operation has been indefinitely delayed by the economy.The company says it made the "difficult but necessary decision" to delay the improvements at its Clairton Coke Works because of a slow economy.The steel company planned to replace three older coke batteries by 2011 and three more by 2014, but now says it's unclear when that work might resume.The upgrades are meant to reduce pollution in the Pittsburgh suburbs most affected, including Clairton, Glassport, Lincoln, Liberty and Port Vue. Pollution readings from the plant have prompted the American Lung Association to rank the greater Pittsburgh area as the sootiest in the country.

Oil jumped to above $51 barrel today as stock markets soared in Asia and Europe and investors saw glimmers of hope that the U.S. economy may be stabilizing.Investors were also focusing on any stimulus and reforms agreed at the ongoing Group of 20 world leaders' summit in London as well as an expected interest rate cut by the European Central Bank.Benchmark crude for May delivery was up $2.92 to $51.31 a barrel by midday in Europe in electronic trading on the New York Mercantile Exchange. The contract fell $1.27 on Wednesday to settle at $48.39.In London, Brent prices rose $3.10 to $51.54 a barrel on the ICE Futures exchange.Oil prices have pulled back from 3-month highs of above $54 a barrel last month as investor optimism that the global recession may be bottoming waned. Still, some investors have taken heart from improving U.S. housing data that the worst could be over.