BP PLC's flawed well design caused the Gulf of Mexico explosion that killed 11 workers and created the worst oil spill in U.S. history, a Transocean Ltd. rig supervisor who survived the disaster says.

The crew and equipment on Transocean's Deepwater Horizon shouldn't be blamed, said Buddy Trahan, who oversees six company rigs in the Gulf, including the now-destroyed facility leased by BP. No one raised any safety concerns when he and BP executives visited the rig on April 20, Trahan said. Hours later, the well erupted in a conflagration that almost killed him.

In his first interview since the accident, Trahan, 43, said it was BP's responsibility to design a safe, efficient plan for drilling a well more than three miles beneath the surface of the Gulf of Mexico. Transocean met its responsibility to provide a well-equipped rig and crew to carry out BP's design, he said.

"The more I learn about this well, the madder I get," Trahan said in the interview at his lawyer's office in Houston. "It is pretty clear to me now it was a screwed-up plan."

The initial explosion hurled him 30 feet through a wall, burning most of the clothing off his back in an instant, Trahan said. He regained consciousness just in time to attract attention as someone ran by. A worker dug him from beneath the rubble and yanked away a steel door whose hinge was stuck in Trahan's neck a half-inch from his carotid artery.

Trahan suffered 12 broken bones and was bleeding heavily from second-degree burns and gashes, including a 9-inch slash across his left thigh and a fist-sized hole in his neck.

"While I was laying on the stretcher, I could see the rig floor engulfed in flames, and that's when I knew we lost everybody on the rig floor, including three who were dear to me," Trahan said.

Trahan last week sued BP, Halliburton Co.'s Halliburton Energy Services and the other Macondo contractors for negligence and "willful, wanton and outrageous conduct." Halliburton provided cementing services for the well.

Trahan hasn't sued Geneva-based Transocean, which continues to pay his salary and medical expenses that he says have topped $1.5 million.

"The overall maintenance on board the Deepwater Horizon met or exceeded regulatory and industry standards," Transocean spokesman Lou Colasuonno said in an e-mail.

Elizabeth Ashford, a BP spokeswoman, had no immediate response to Trahan's comments.

Cathy Mann, a Halliburton spokeswoman, defended the company's work, saying the contractor carried out BP's well design.

At one point, Halliburton recommended 21 centralizers be used to center the well casing in the hole, reducing the risk of channels forming in the cement that would allow gas to flow. BP decided to use six of the devices, according to a letter that U.S. Reps. Henry Waxman of California and Bart Stupak of Michigan sent to BP's Chief Executive, Tony Hayward, in June.

Trahan works at Transocean's Houston operations headquarters for the company's deep-water unit, Transocean Offshore Deepwater Drilling Inc. He oversees rig-equipment maintenance, long-term repairs and supplies, and isn't in the chain of command that interacts with customers about well design. He says he has pieced together his conclusion from testimony at public hearings and from documents BP, Transocean and other companies have turned over to Congress.

Trahan ticked off perceived flaws in the well design on his scarred fingers: Using foam cement in a high-pressure gas well, failing to employ a safer casing type, installing inadequate centralizers to insure the wall was properly cemented, and failing to test the well's integrity before removing heavy drilling mud that was holding back pressure in the well.

"I've worked on jobs for BP, Chevron and Shell, and I've never seen this combination of bad choices on any other well, ever," he said.