Feinstein's bill would cut federal incentives for oil and gas companies working in waters deeper than 1,300 feet.
"The BP spill (in 2010) illustrated just how devastating oil spills in deep water can be," she said in a statement. "But even though we understand the great risks and lack the technology to drill safely, unwise incentives that push oil companies to drill deeper and deeper remain in place."
A New Orleans court is weighing responsibility for the deadly 2010 spill in the deep waters of the Gulf of Mexico, the worst in U.S. history.
Nelson's measure would change tax codes so that companies can't write off the expenses related to spill-related spending.
"Given the record profits of the big oil companies, I don't think they need any more help from taxpayers," he said.
Their Republican rivals have pressed the government to take advantage of the national oil and natural gas boom through more onshore and offshore work.