* Ironically blasts came as BP officials celebrated safety
* Professor discloses transcripts of survivors' interviews
* Offshore rig leased by BP exploded and sank last month
(Adds BP confirmation of executives on board rig)
By Chris Baltimore
HOUSTON, May 8 A natural gas cloud enveloped a
Gulf of Mexico offshore oil rig leased by BP Plc (BP.L) and
exploded just as visiting BP officials were celebrating seven
accident-free years in the rig's crew quarters, according to
accounts by survivors of the accident.
Robert Bea, a University of California Berkeley engineering
professor, said on Saturday he obtained transcripts of
interviews from three rig workers familiar with the explosion,
including two who were in the rig's crew quarters at the time.
The interviews were done as part of BP's internal
investigation of the accident but had not been made public.
Swiss-based Transocean Ltd's (RIGN.S) (RIG.N) Deepwater
Horizon rig, under contract with BP, exploded and caught fire
on April 20 while it was putting the finishing touches on a
well about a mile (1.6 km) beneath the ocean surface. It sank
two days later.
The accident has triggered a huge oil spill posing an
environmental and economic disaster to the U.S. Gulf Coast.
As rig workers and engineers on the deck of the rig were
finishing a delicate operation to cement the metal well casing
in place, something went horribly wrong.
According to the transcripts, a giant bubble of methane gas
rushed up the drill pipe and enveloped the deck of the drilling
platform in a cloud of highly flammable gas, followed by a
scalding flood of crude oil that spilled onto the drill deck
Nine workers on the drill deck were killed, along with two
others working in the nearby mud storage room, Bea said.
"Gas and oil rushed up the riser. There was little wind and
a gas cloud got all over the rig," according to a transcript
from a rig worker recited by Bea in a telephone interview.
The drill deck itself is "intrinsically safe," meaning it
is free of any sources that can cause a spark such as a spark
plug in a generator, Bea said.
But the methane flood that rushed up the drill pipe was so
immense it soon spread across the entire length of the massive
drilling platform, Bea said.
When the gas reached a room where mud used in well-drilling
was stored, sparks from engines running pumps there ignited the
gas cloud, according to the transcript.
"When the main inductions of the engines got a whiff (of
the gas) they ran away and exploded -- blew them right off the
rig," the transcript said. "This set everything on fire."
In the living quarters next to the mud storage room,
off-duty crew and visiting BP officials were celebrating seven
years of accident-free operation of the rig, according to the
transcript. The explosion blew the walls off the crew quarters
and sent furniture and people flying.
The blast "took out all of the interior walls where
everyone was hanging out having -- I am not making this up -- a
party to celebrate seven years of accident-free work on this
rig," the transcript said.
"The furniture and walls trapped some, broke some bones,
but they all managed to get in the lifeboats with assistance
from others," the transcript said.
A BP executive confirmed on Saturday that seven BP
employees had been on the rig, from young engineers to a vice
president for Gulf of Mexico drilling operations. All escaped
safely, said Doug Suttles, BP's chief operating officer.
"One of the reasons the more senior members were there was
to discuss the safety performance of this rig," Suttles told
reporters at a briefing in Robert, Louisiana. "This rig had an
outstanding record. I think it had gone over 2,500 days without
a significant safety accident."
(Editing by Will Dunham and Todd Eastham)