The massive oil spill in the Gulf of Mexico is causing a rift among once-friendly downtown trade associations that are now at odds over whose members caused the disaster.

Longtime allies such as the American Petroleum Institute, the International Association of Drilling Contractors and the National Ocean Industries Association are circling the wagons to protect their biggest dues-paying companies until more details about the accident emerge, one of the groups told Roll Call on Wednesday.

“We’re keeping ourselves a little bit at arm’s length until we know more,” said Brian Petty, a spokesman for the drillers group IADC.

Prior to the spill, Petty described his trade association’s relationship with API as “very close.”

The three trade groups represent the complex overlay of oil companies, contractors, equipment makers and service firms needed to pump oil from thousands of feet below the ocean floor.

In the case of BP’s Deepwater Horizon, which sank two weeks ago, the gasoline retailer actually contracted much of its operations with Transocean, a Houston-based drilling firm whose employees also manned the platform. Another company, Cameron International, made the safety valve that apparently failed initially to stop the leak, while Halliburton employees poured concrete on the job site, sources said.

According to its website, API’s membership includes three of the companies: BP America, Halliburton and Cameron International. A NOIA spokeswoman confirmed that all four companies are members, while Transocean is the only one of the four companies with full membership in IADC, the drillers website shows.

“API is going to be loath to step out in front of BP,” Petty said. “British Petroleum is such a huge member of API, API is not going to do anything to compromise BP’s position. BP has been pointing fingers at Transocean, BP has been pointing fingers at Halliburton, BP has been pointing fingers at Cameron, trying to hive off the blame.

“And the National Ocean Industries Association?” Petty continued. “Similarly, they’ve got Transocean as a member but also BP, so BP has kind of kept a boot on their neck.”

A BP spokesman did not respond to a request for comment Wednesday. API and NOIA both denied that interaction among the groups is deteriorating.

API spokeswoman Cathy Landry disputed a claim that API is only looking out for BP’s interests in the aftermath of the Gulf of Mexico spill.

“We are not carrying anybody’s water,” she said.

With the well still flowing Wednesday, Landry said all of API’s members have “roughly the same interests.”

“Our goal is to one, stop this spill; two, clean it up; and three, find out what went wrong and implement policies and practices to further improve our industries,” she said.

Counting all four of the companies as members, NOIA is undoubtedly sorting through its own thick internal morass involving how to triage its often-conflicted members’ lobbying strategies.

In an interview, NOIA spokeswoman Nicolette Nye also denied there is dissension — internally or on K Street — among the three trade associations. Regarding her organization, she said the association is “standing by our member companies.”

“As an association, we’re trying not to point fingers. It’s pretty evident that those under the microscope now are trying to point fingers,” she said. “We’re going to wait for an investigation and it’s going to all come out in due time.”

“The collective energy of everybody should be stopping this leak and preventing further damage,” she added. “We can start playing the blame game later.”

Until the spill’s culprit is found, Petty said, he expects all three of the trade groups to keep a low lobbying profile while playing the waiting game.

In the coming weeks, he expects more meetings between BP and Transocean bosses as well as lawmakers and executives, similar to closed-door meetings held Tuesday by Rep. Ed Markey (D-Mass.), the chairman of the top House subcommittee on energy and the environment.

“At this point we’re just responding to inquiries and subpoenas. … Since we don’t know what happened, it’s hard to allocate blame or prescribe new regulatory initiatives,” he said.

“There will be other hearings, especially as the spill expands. … You can bet that the environmental committees are going to get into it, so we’re just bracing for it.”