The bill faces an uncertain future and is likely to get lumped into a year-end debate in which lawmakers tackle the so-called fiscal cliff - a combination of the expiration of Bush-era tax cuts and $110 billion in automatic spending cuts to the Pentagon and domestic programs that, taken together, have the potential to drive the economy back into recession.
The action came as Congress limped out of town for a five-week vacation.
The cost of Thursday's package ballooned by more than $50 billion since its release on Wednesday, including a production tax credit for wind and other renewable energy producers of electricity criticized by presumptive GOP nominee Mitt Romney. That provision was initially targeted for elimination, but garnered critical support from Republicans like Charles Grassley of Iowa.
Sen. Jon Kyl (R., Ariz.) engineered the revival of a tax break for builders of NASCAR tracks and other motorsports facilities after it had originally faced the chopping block. He was one of five conservative Republicans who opposed the overall measure, however.
Panel members said the exercise in legislative sausage making was actually a step forward for tax reform because they had summoned the courage to allow almost 20 tax breaks to expire. They included a much-criticized tax credit for ethanol producers.
Top panel Republican Orrin G. Hatch of Utah - a longtime proponent of a popular tax credit for businesses that invest in research and development - said Thursday's developments represented progress given that the number of tax breaks in the annual "extenders" debate had ballooned from 42 in 1998 to 154 last year.
"The tide is turning," Hatch said. "For the first time in my 21 years on this committee, we are deliberately moving in the opposite direction."
