LONDON (MarketWatch) -- BP didn't provide the leadership, resources or structure needed for effective safety at its five U.S. refineries, leading to "material" problems at all of them, a committee led by former Secretary of State James Baker said Tuesday.

The report, commissioned after an explosion killed 15 people at a Texas City refinery in 2005, singled out Chief Executive John Browne for paying too much attention to environmental issues and not enough to safety at his own refineries.

"In hindsight, the panel believes that if Browne had demonstrated comparable leadership on and commitment to process safety, that leadership and commitment would likely have resulted in a higher level of process-safety performance in BP's U.S. refineries," the Baker panel wrote in a 374-page report.

Browne last week brought forward his retirement date by nearly a year and a half, agreeing to turn the reigns in August over to Tony Hayward, head of exploration and production at the company. See full story on Browne's surprise resignation.

The panel charged that the oil giant wrongly concluded that fewer personal mishaps -- such as slips, falls and vehicle accidents -- were a sign that the company's safety culture was sound, when the company process-safety culture was lacking.

"The panel found that BP has not implemented an integrated, comprehensive, and effective process-safety-management system for its five U.S. refineries," the company said.

BP has agreed to implement the panel's recommendations. These include making an integrated and comprehensive process-safety-management system, having an audit system for process safety, and monitoring process safety at the board level. See external link to the Baker report.

BP will spend $200 million to pay for 300 external experts to conduct audits and redesigns. It's also set aside $1.6 billion to compensate victims of the Texas City explosion, which also injured 170 people.

BP has previously committed to spend more on maintenance, inspections and training at its refineries, on average $1.7 billion a year from 2007 to 2010.

"Browne's recent presentations within BP appear to acknowledge the previous underinvestment and to suggest that it was largely the result of an inability on the part of refining-line management to see the need to spend more money," the committee wrote.

'[T]he panel believes that if Browne had demonstrated comparable leadership on and commitment to process safety, that leadership and commitment would likely have resulted in a higher level of process-safety performance.' — Excerpt of committee report

Workers at three of the five U.S. refineries -- in Texas City; Toledo, Ohio; and Whiting, Ind. -- complained about the lack of funding, the panel found.

That said, the Baker panel didn't find evidence that management deliberately withheld funding.

BP management also "overloaded" refinery at its personnel with so many company-wide initiatives that employees couldn't keep up, the report charged. Turnover of managers at the plants -- again, notably in Texas City, Toledo and Whiting -- also contributed to process-safety weakness.

The Baker report wasn't as critical of BP's two other refineries, in Cherry Point, Wash., and Carson, Calif. The Cherry Point refinery has a "very positive, open and trusting environment," while Carson's environment was "generally" positive. The panel pointed out that the culture at these refineries was established before BP bought them from Arco.

U.S.-listed BP shares fell 1.8% in late morning trade, though the broader sector also saw pressure on further oil-price weakness.