The brewing nominations standoff doesn’t look likely to doom President Barack Obama’s choice to head the Environmental Protection Agency, but a hold on Gina McCarthy from a top Senate Republican remains in effect.

Sen. David Vitter of Louisiana announced at the Senate Republican Conference’s weekly lunch meeting that he wouldn’t back a bid to filibuster the McCarthy nomination after receiving a variety of assurances about transparency from the agency. Vitter, the top Republican on the Environment and Public Works panel, previously held up the committee vote on her nomination.

Vitter’s office released a statement shortly after announcing his decision to fellow GOP senators, thus making the news public.

“I’ve had very productive conversations with EPA over the last several weeks, and believe the agency has taken significant steps forward on our five transparency requests,” Vitter said. “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.”

There was still no announcement of a resolution to a disagreement between the Obama administration and Missouri Republican Sen. Roy Blunt regarding delays in implementation of the St. Johns Bayou-New Madrid Floodway Project.

The dispute prompted Blunt to place a hold on McCarthy’s nomination.

“As the saying goes, you’re entitled to your own opinion, but you’re not entitled to your own facts. The government needs to stop arguing with the government. I look forward to hearing conclusively whether the Corps, EPA, and FWS have reached an agreement on all of the facts surrounding this project, as they committed to do by March 15, 2013,” Blunt wrote in a Tuesday letter to the Army Corps of Engineers, EPA and the Fish and Wildlife Service.

Absent an agreement with Blunt, Majority Leader Harry Reid, D-Nev., would still need to file a motion to limit debate to get the McCarthy nomination up for a vote. Vitter’s announcement suggests that Reid could prevail on that motion, however.

Reid said Tuesday that he planned to detail a path forward on pending nominations following a Thursday Democratic caucus lunch.