We've just published an investigation into BP's systematic disregard for worker safety and environmental rules in its North American operations. Co-published with The Washington Post, the story cites a string of internal BP probes that warned about the risk of serious accidents. These internal probes flagged safety problems with BP operations all over the country, from Alaska's North Slope to refineries in Texas City and Los Angeles.

Check out the documents at the center of our story:

A 2001 company report, done in response to safety concerns by workers at Greater Prudhoe Bay oil field in Alaska, concluded that "workers are told safety is a BP priority, but there is a disconnect between GPB (Great Prudhoe Bay) management's stated commitment to safety and the perception of that commitment." The report continued: "Many workers believe, based on actions taken, that achieving short-term budget targets is GPB management's first priority."

But the troubles in Alaska weren't addressed following that report. An outside law firm hired by BP to investigate worker complaints produced another report in 2004. That report found that managers were saving maintenance costs by running equipment to the ground and that workers operated in a "climate of perceived intimidation and threatened retaliation."

Then there's a 2007 blue ribbon report, commissioned by BP after a Texas City refinery explosion in 2005 killed 15 workers. That report found that "while some refineries are far more effective than others in promoting process safety, significant process safety culture issues exist at all five U.S. refineries, not just Texas City." It continued: "The Panel found instances of a lack  of operating discipline, toleration of serious deviations from safe operating practices, and  apparent complacency toward serious process safety risks at each refinery."

That's something that California officials already had a hint of, at least in regard to a BP refinery in the Los Angeles area.

In 2002, inspectors with Southern California's air quality agency noticed that BP's inspection reports for that refinery looked too good to be true. When they went to investigate, BP turned them away, and when the inspectors finally obtained a warrant to inspect, they found equipment and facilities in enough disrepair to lead to thousands of violations. The agency sued, and BP eventually settled, agreeing to pay more than $100 million without admitting guilt. You can read that lawsuit here.

Our full investigation has all the details -- terse warnings from state regulators, technicians who raised safety concerns and were fired soon after, and missing documents for another BP drilling project in the Gulf. Read the whole story.

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