The ranking Republican on the Senate Environment and Public Works Committee said Tuesday he would no longer block the nomination of Environmental Protection Agency official Gina McCarthy to head that agency and would support a vote on the Senate floor without a filibuster.

Sen. David Vitter (La.) said he had changed his position after “major progress” was made on five demands he and other committee Republicans made of the EPA.

“These are huge, significant steps forward to bringing transparency to the agency, and I see no further reason to block Gina McCarthy’s nomination, and I’ll support moving to an up-or-down vote on her nomination,” Vitter said in a statement on his Web site.

McCarthy, the EPA’s assistant administrator in charge of air and radiation, still faces a hold on her nomination from Sen. Roy Blunt (R-Mo.). Blunt said he is not satisfied that the EPA, Army Corps of Engineers and U.S. Fish and Wildlife Service agree on facts about a floodway project in his state.

President Obama nominated McCarthy to head the EPA in March, and she was approved by the committee in May. But Vitter has been threatening a filibuster over what he calls “transparency” issues involving the agency.

Vitter said Tuesday he is now satisfied with the results of negotiations with the EPA. He said the agency has agreed to retrain its more than 17,000 workers on records maintenance and use of personal e-mail accounts; find ways to allow outsiders to analyze the science behind some air regulations; and publish on two Web sites notices of intent to sue and petitions for rulemaking, among other issues.