Internal documents released to The New York Times last week show that BP reported problems mid-March with the undersea well that exploded a month later. However, the company delayed the testing of a critical piece of equipment ? the well’s blowout preventer. And some BP engineers expressed concerns about the oil rig’s safety as far back as 11 months ago.

Ian Urbina authored an article for The Times exposing BP’s early worries about the oil rig’s safety. He explains what BP knew, when, and examines the response to the emerging safety problems. We also check in with Dean Blanchard, a seafood wholesaler whose early suspicions about BP’s negligence have proven to be well-founded.