Laying the groundwork for what may become the first environmental law signed by President Bush, the U.S. Senate yesterday voted 99-0 to more than double spending to clean up of hundreds of thousands of moderately contaminated and abandoned industrial sites around the country. In the past, developers have often steered clear of the sites, known as brownfields, because they didn’t want to be held liable under the Superfund law for messes they didn’t create. The bill, which is expected to be approved by the House, would protect developers from U.S. EPA lawsuits and Superfund fines relating to pollution left by earlier owners. Republican senators in recent years have prevented the brownfields bill from reaching the Senate floor because they wanted the issue addressed as part of a broader review of Superfund — but this year, the White House gave the nod to the bill and the vote went forward.