NEW ORLEANS, La. — Transocean employees should have done more to detect signs of trouble before the company’s drilling rig exploded in the Gulf of Mexico in 2010, killing 11 workers and triggering the nation’s worst offshore oil spill, the company’s chief executive testified Tuesday.

However, the Swiss-based drilling company’s own investigation of the disaster didn’t find any mistakes beyond the rig floor, Transocean Ltd. president and CEO Steven Newman said. He testified on the 14th day of a trial designed to determine the causes of BP’s well blowout and to assign fault to the companies involved.

Newman said Transocean didn’t identify any “management failures” that led to the blowout.

“I think we had a good system in place,” he said.

Newman testified that Transocean agreed in January to plead guilty to a criminal charge of violating the Clean Water Act because its rig workers on the Deepwater Horizon played a role in botching a crucial safety test before the blowout.

“Do you blame the crew that night?” Transocean attorney Brad Brian asked Newman.

“Do I blame the crew? Do I wish the crew would have done more? Absolutely. I am not sure that that’s the same emotional content as blame,” Newman said.

Newman, however, said BP ultimately was responsible for deciding how to perform the safety test and for determining whether it was successful.

Two BP rig supervisors, Robert Kaluza and Donald Vidrine, are charged with manslaughter in the 11 rig workers’ deaths and await a separate trial. An indictment last year accused Kaluza and Vidrine of disregarding abnormally high pressure readings during the safety test.

No Transocean employees have been charged with crimes, but the company pleaded guilty to the misdemeanor charge in February and agreed to pay $1.4 billion in criminal and civil penalties as part of a settlement with the Justice Department.

BP’s internal investigation of the blowout also spared its own upper-level managers from any blame. Instead, the London-based oil giant issued a report that outlined a series of mistakes by rig workers and faulted decisions by other companies.

Newman touted the company’s safety culture, saying any rig worker is empowered to call a halt to a drilling operation. If a worker sees any cause for concern, he said, “You not only have the right but the obligation to call a timeout.”

“Safety is one of our core values,” Newman said. “I think it is fundamental to what we do. “

He also praised the Deepwater Horizon for its “exemplary track record” before the Macondo blowout and for doing “some pretty amazing things,” including drilling a different BP-owned well in the Gulf to a record depth of 35,050 feet in 2009.

“The Deepwater Horizon was one our best performing rigs,” he said.

Elsewhere, 2009 was a rough year for Transocean. Newman said the company temporarily suspended operations on its entire fleet of rigs after four workers were killed in separate incidents within a 92-day period that year.

“I don’t think there’s any other conclusion you can draw than we had a problem,” Newman said during cross-examination by plaintiffs’ attorney Robert Cunningham.

The deaths, coupled with an increasing number of “high-potential incidents,” prompted Newman to order an independent review of the company’s safety management system.

“I think sometimes the difference between a high-potential incident and an actual injury is nothing more than luck,” Newman said, citing an example of rig equipment that falls harmlessly to the deck instead of hitting somebody.

“Are you telling us that control of high-potential incidents such as what occurred on the Deepwater Horizon is a matter of luck?” Cunningham asked. “Is that Transocean’s safety philosophy?”

“Absolutely not,” Newman responded. “Our objective is to prevent all incidents.”

Newman closed out his testimony by saying he thinks every day about the 11 men who died.

“Why?” Brian asked him.

After a long pause, Newman cleared his throat and answered, “Because I ask myself if there isn’t something more I could have done.”

U.S. District Judge Carl Barbier is hearing testimony without a jury and, barring a settlement, could decide how much more money BP and its contractors should pay for their roles in the catastrophe.

Barbier also heard testimony Tuesday from Tim Quirk, who was a laboratory manager for Halliburton, BP’s cement contractor on the Deepwater Horizon.

Shortly after the blowout, Quirk performed tests on a cement slurry with the same composition of what was used at the Macondo well. But he said another Halliburton employee instructed him not to submit a written report on the test results and only share them verbally.

“It was a little unusual,” he said of the instruction.

Quirk said he complied and threw away his notes.

“Looking way back at it now, I can understand the importance of it. But back then I just didn’t see it that way,” he said, noting that he had used “off-the-shelf” lab ingredients for the test.

Last week, Halliburton attorney Donald Godwin told Barbier that the company only recently discovered cement samples that weren’t turned over to the Justice Department after the spill.

Godwin said Halliburton believes the material found last Wednesday at its laboratory in Lafayette has no bearing on the trial, but plaintiffs’ attorney Jeffrey Breit said the samples are cement a Halliburton employee used for testing of the Macondo well.

Quirk said he secured all of the samples he believed were related to the Macondo well in a locker and put everything else in a warehouse, never suspecting the recently discovered samples could be related to the case.

“I had no way of knowing,” he said.