Legislative sources said that lawmakers negotiating legislation that will impose an impact fee on natural gas wells in the Marcellus Shale have numerous issues to resolve, leaving the timing for a final vote still up in the air.

For his part, state Sen. Joe Scarnati, R-Jefferson, the president pro tempore, said he would like to see approval of the measure occur before Gov. Tom Corbett delivers his budget address, which is scheduled for Feb. 7. But sources say a vote in the next few weeks is unlikely.