HARRISBURG — A proposed compromise on legislation to ban smoking in most public places in Pennsylvania stalled Monday after Gov. Ed Rendell and Democratic senators insisted that state law should not stop municipalities from enforcing stronger prohibitions.

Rendell even issued a veto threat, just hours before a joint House-Senate committee was to meet to vote on legislation that has been mired in disagreement between the two chambers for 10 months.

The governor, who has made a smoking ban part of an effort to reduce health care costs, told reporters Monday he would reject a bill that contains too many exemptions or wipes out a stronger ban enacted by the city of Philadelphia.

"I have told legislative leaders, if they send me a bill that's too watered down or pre-empts, for example, what Philadelphia's done, I will veto it," Rendell told reporters at an unrelated public event in the Capitol.

Sen. Chuck McIlhinney, who wrote the compromise bill, said the six-member conference committee was ready to vote on his bill Monday until support failed for a law that would bar any local prohibitions. McIlhinney's proposed bill would prevent local governments from enacting their own smoking prohibitions and would have blocked enforcement of Philadelphia's ban.

The committee's lone Senate Democrat, Robert J. Mellow of Lackawanna County, got cold feet after Rendell's veto threat, McIlhinney said.

"This whole issue is coming down to Philadelphia getting its own law or not," McIlhinney, R-Bucks, said.

Mellow disputed that, saying Senate Democrats discussed the matter Monday independently of Rendell's veto threat, and decided that they would not support a bill that prohibits any local smoking ban, even if the bill allowed Philadelphia's to remain standing.

Philadelphia's Democratic senators want the city to be able to enforce its ban, Pittsburgh's Democratic senators want the city to have the option of enacting its own ban and Scranton should be able to enact its own ban, as well, Mellow said.

"To me it just sounds like it would be the right thing to do," said Mellow, the Senate's Democratic leader from Lackawanna County.

As a result, he assembled a plan to offer an amendment to McIlhinney's bill that would allow municipalities to enact their own smoking bans, Mellow said.