HARRISBURG - Pennsylvania's former environmental protection chief on Monday became the first Democrat to make it known he will challenge Gov. Corbett in 2014.

John Hanger, 55, who served as secretary of the Department of Environmental Protection, said he would make his intentions known in a series of announcements beginning Wednesday in Philadelphia and Harrisburg.

A lawyer, Hanger served on the Public Utility Commission for five years in the 1990s and headed the DEP under Gov. Ed Rendell for nearly three years. He also was founding president of the environmental group PennFuture.

In an interview Monday, he cited his experience and said the Republican governor's policies, particularly on education and the economy, should be challenged. "Gov. Corbett's first two years have been a disaster for this state," Hanger contended.

His is the first hat tossed into what could become a crowded Democratic ring. Millionaire Tom Knox, who ran for mayor of Philadelphia in 2007, and York businessman Tom Wolfe, who served as Rendell's revenue secretary, have told the Associated Press they, too, might run.

Among other names mentioned in Democratic circles: former U.S. Rep. Joe Sestak, who narrowly lost a 2010 run for the U.S. Senate; Attorney General-elect Kathleen Kane, who won more votes statewide than President Obama on Nov. 6; Allentown Mayor Ed Pawlowski; state Treasurer Rob McCord and U.S. Rep. Allyson Y. Schwartz, both of whom just were reelected; and Jack Wagner, the retiring state auditor general.

The state's top Democratic officeholder, U.S. Sen. Bob Casey, who was just reelected, has said he is happy in the Senate.

Democrats' strong showing in Pennsylvania on Nov. 6, along with Corbett's tepid poll numbers, make the prospect of a historic unseating of an incumbent governor attractive, experts say. Since 1970, every Pennsylvania governor who has sought a second term has won reelection.

Corbett, who reaches the midpoint of his term in January, has been controversial for deep spending cuts in aid to public schools and universities. But as he regularly points out, he has kept his campaign promises to sign budgets on time and not raise taxes.