ProPublica offers its latest joint investigative effort today with The Washington Post that takes a look at BP's past internal warnings about the risk of potential oil-drilling problems.

“A series of internal investigations over the past decade warned senior BP managers that the oil company repeatedly disregarded safety and environmental rules and risked a serious accident if it did not change its ways,” the story begins. “The confidential inquiries, which have not previously been made public, focused on a rash of problems at BP's Alaska oil-drilling operations. They described instances in which management flouted safety by neglecting aging equipment, pressured employees not to report problems and cut short or delayed inspections to reduce production costs.”

The story also indicates internal BP staffers are not happy with the company's actions, noting: “The reports detailing the firm's Alaska investigations -- conducted by outside lawyers and an internal BP committee in 2001, 2004 and 2007 -- were provided to ProPublica by a person close to the company who thinks it has not done enough to fix its shortcomings.”

Another sign that non-profit news outlets like ProPublica are having an impact.