Federal investigators seeking the cause of the rig explosion that led to BP’s massive Gulf oil spill focused Monday on communication and chain of command, wondering at times whether the key players knew enough to handle an emergency.

Neil Cramond, who oversees BP’s marine operations in the Gulf, acknowledged he rarely had contact with Paul Johnson, who managed the Deepwater Horizon rig for owner Transocean Ltd., which leased it to BP.

The rig exploded April 20, killing 11 workers and spewing 206 million gallons of oil into the sea before a temporary cap stopped the flow in mid-July.

Cramond also testified that captains of rigs like the Deepwater Horizon are ultimately responsible for crew safety and environmental matters, but are not always involved in decisions about how to deal with drilling operations and potential risks.

Members of the joint U.S. Coast Guard-Bureau of Energy Management, Regulation and Enforcement investigative panel are trying to figure out what caused the explosion and how regulation, safety and oversight can be improved to prevent another such catastrophe.

Cramond’s description of how responsibilities and communication were divided among the parties responsible for the sunken rig raised eyebrows at times among the investigators.

While questioning Cramond, a Coast Guard official wondered if there was anyone who had a “big picture” of what was going on. He said he was concerned the captain was responsible for keeping the crew and vessel safe and preventing pollution, but had “little say and awareness of what’s going on in terms of risk.”

“I believe what you’ve outlined is an accurate picture,” Cramond said, noting such arrangements are standard in the oil and gas industry.

He insisted, however, that records will show that on a number of occasions he communicated concerns about safety problems to the people who needed to know about them.

Asked if the Deepwater Horizon was properly manned at the time of the explosion that killed 11 workers, he replied: “I have no information that would say otherwise.”

Johnson, whose responsibilities included training and personnel, was not on board the Deepwater Horizon when it exploded. He testified Monday that the blast knocked out communication between him and the captain and offshore installation manager.

In March, barely a month before the accident, one of Cramond’s employees visited the Deepwater Horizon to ensure Transocean had resolved safety violations found in a random audit a year earlier that forced the rig to shut down for five days.

Cramond said 63 of 70 issues had been resolved, and the remainder were minor problems that the company was given six months to resolve.

Cramond, however, could answer almost no questions regarding the drilling side of the operation, insisting his responsibility was largely to determine whether the vessel was able to remain seabound. He did, however, acknowledge that several systems and pieces of equipment overlapped, saying a Transocean employee was ultimately responsible for having a broader idea of what was happening on the rig as a whole.

Asked if there was a process in place to ensure direct communication between the different parties overseeing the rig’s operation, Cramond said: “I can’t completely answer that question.”

In addition to operating the rig that exploded, BP owned a majority interest in the ruptured undersea well. Anadarko Petroleum held a minority interest in the well.

The hearings in Houston were scheduled to run through Friday. They are the fourth set of hearings by the panel, which isn’t expected to issue any conclusions for months.

The temporary cap placed on the blown-out well in mid-July has kept any more oil from spewing, and the final sealing should take place after Labor Day.

Engineers are preparing to first remove the failed blowout preventer — a key piece of evidence — and replace it with another. After that, they will complete the drilling of a relief well, then will plug the blown-out well for good by pumping mud and cement into the bottom.

The blowout preventer was intended to prevent an explosion like the one on the Deepwater Horizon and the subsequent leak.

There are three pieces of pipe from the well inside the blowout preventer that engineers want to remove before attempting to replace it, retired Coast Guard Adm. Thad Allen, the government’s point man on the spill response, told reporters Monday.

“It’s obviously harder if the pipe is still in the blowout preventer,” Allen said.

Tests will be run inside the blowout preventer and the temporary cap to determine the best way to remove the pipes, Allen said.

Allen has ordered BP to have live undersea cameras trained on the well during the prelude to the so-called bottom kill. He said he also has told BP to have methods in place to collect any oil that may be released during the procedures.

BP intends to remove the temporary cap as part of the blowout preventer replacement procedure, indicating officials are confident an earlier procedure to plug the well from the top will hold the oil in.