Though he couldn't travel to Pittsburgh yesterday, a national health care advocate told a local group that the nation could be facing a historic opportunity to reform the U.S. health care system.

Increased health care costs and growing numbers of uninsured people have helped fuel momentum for change among employers, unions, health care providers and other groups, Ron Pollack, executive director of Families USA, told about 100 people gathered for the annual meeting of the Consumer Health Coalition at the Sen. John Heinz History Center.

He was scheduled to appear at the event, but spoke by speaker phone from Dulles International Airport outside Washington, D.C., where his scheduled flight was grounded because of mechanical programs.

Mr. Pollack said significant change is much more likely if either of the Democratic nominees battling for the party's nomination, Sens. Hillary Rodham Clinton or Barack Obama, becomes president.

Both candidates have more detailed plans for expanding access to health care than the likely Republican nominee, Sen. John McCain, whose proposals focus more on cost containment.

In an interview, Mr. Pollack spoke in support of Cover All Pennsylvanians, Gov. Ed Rendell's plan for making affordable coverage available to the state's uninsured adults.

Jessica Seabury, the Consumer Health Coalition's executive director, said her group also supports the governor's proposed insurance changes, including limiting the ability of insurers to consider health history in setting rates.