METAIRIE, La. — BP interfered with critical efforts to lower an undersea robot to try to close the device that failed to stop the massive Gulf of Mexico oil spill because of concerns over heat buildup from the burning rig, a salvage firm executive said yesterday.

The testimony came from Doug Martin, president of Smit Salvage Americas, which was hired to help try to save the Deepwater Horizon rig after it exploded. He told a federal investigative panel that in the hours after the April 20 disaster, he thought it was important to get the robot into the water as quickly as possible so engineers could choke off the oil.

But, Martin said, BP officials discussed calculating how the heat from the fire would affect the boat that was to launch the robot. He said he believed that it was a waste of time and that BP was interfering.

“When they wanted to calculate the heat load on the boat, I said, ‘How do you know how hot the fire is?’ ’’ Martin told the joint US Coast Guard-Bureau of Energy Management, Regulation, and Enforcement investigative panel. “I had a hard time believing there was data available at that time to do that. That’s why I felt it was better just to keep the boat cool and use common-sense tools to get the [remotely operated vehicle] in the water.’’

Martin said several hours went by before the undersea robot was lowered into the water.

Engineers were unable to close the so-called blowout preventer that failed to stop the spill, and the rig eventually sank. Eleven workers were killed in the rig explosion, and some 206 million gallons of oil spewed from BP PLC’s undersea well, according to government estimates.

A BP spokesman said in a e-mailed statement that the company “performed critical safety calculations before deploying the ROV to ensure that this operation did not put workers in harm’s way.’’

The federal panel meeting this week at a hotel near New Orleans is trying to determine the cause of the blast and massive oil spill that followed.

Besides figuring out a cause, the panel, which is holding its fifth series of hearings, is examining how to improve safety and oversight.

At least one more series of hearings is expected before the panel members begin collaborating on their report.

Also at the hearings yesterday, a US Coast Guard official testified that the fact that 115 people on the 126-member crew escaped the Gulf of Mexico rig explosion is a sign the evacuation effort went fairly well. But oil industry partners, because of their expertise, are needed to help the government during such a disaster, the official said.

Captain James Hanzalik, chief of incident response for the Coast Guard’s Eighth District, told the investigative panel there was nothing more his agency could have done to prevent the rig from sinking.

Hanzalik also said the Coast Guard relies on oil industry partners for help in rescuing so many people.

“Typically we don’t have the assets to do that,’’ Hanzalik said.

Fighting the fire on the rig is largely the responsibility of the industry, Hanzalik said. “We’re not trained firefighters,’’ he said.

Among the witnesses scheduled to testify later this week are key workers for BP and Transocean , a specialist on mobile offshore drilling units, a specialist on maritime alarm systems, and a deep-water well equipment specialist.

Perhaps the most critical testimony is expected to come from two BP officials who were familiar with the company’s decision to use only six centralizers during the cementing of the well that blew out. Halliburton had recommended the use of 21 centralizers, which are devices that make sure the casing is running down the center of the well bore. If the casing is cemented off-center, there is a risk of an imperfect seal that could allow oil and gas to escape.

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