The BP Oil Commission’s lead investigator, Fred Bartlit, refused to blame any firm involved in the Gulf of Mexico spill, saying that a combination of factors caused the deadly explosion at the Macondo oil well on April 20.

Bartlit presented preliminary findings at the opening of the presidentially appointed commission’s Nov. 8-9 public meeting in Washington, D.C. He said BP and workers on the oil rig made conscious decisions to depart from the planned procedures in light of unexpected developments, and some of those decisions may have made sense.

There is no evidence to suggest those decisions were financially based, Bartlit added. “To date, we have not seen a conscious decision of any individual who considered dollars over safety,” he said. Some critics in hearings on Capitol Hill have alleged BP put profits ahead of safety concerns at the well.

He also said his preliminary findings support “about 90%” of the conclusions drawn from BP’s own investigative report, released in September, which found that no single factor caused the explosion. BP said that the explosion occurred as a result of a complex sequence of failures.

But Bartlit and his co-investigators reiterated conclusions from his own Oct. 28 report, which identified problems with the cement foam used as a barrier between the well’s casing and interior (ENR 11/8/10 p. 60). Moreover, a negative pressure test repeatedly showed the primary cement job had not isolated hydrocarbons within the reservoir.

Despite those results, BP and Transocean personnel treated the negative pressure test as “a complete success,” Bartlit concluded in written remarks.

The commission is expected to release a final report in January.