Workers add drilling pipes on the rotary table of a natural gas drilling rig near Towanda, Pennsylvania, February 3, 2010. Energy companies drilling for natural gas in Pennsylvania�s Marcellus Shale would have to pay a wellhead tax under a proposal unveiled on Tuesday by Gov. Ed Rendell. Rendell wants to charge drillers 5 percent of the value of gas at the wellhead plus 4.7 cents per 1,000 cubic feet of gas taken from the ground, starting July 1. The plan would raise $160.7 million in the first year and $1.8 billion over five years. Photo taken February 3.