From the Washington Post:

A rule change two years ago by the federal agency that regulates offshore oil rigs allowed BP to avoid filing a plan specifically for handling a major spill from an uncontrolled blowout at its Deepwater Horizon project - exactly the kind of disaster now unfolding in the Gulf of Mexico.

Oil rig operators generally are required to submit a detailed "blowout scenario." But the federal Minerals Management Service issued a notice in 2008 that exempted some drilling projects in the Gulf under certain conditions.

BP met those conditions, according to MMS, and as a result, the oil company had no plan written specifically for the Deepwater Horizon project, an Associated Press review of government and industry documents found.

In industry in bed with the regulators? From the same article:

In 2008, the Interior Department took disciplinary action against eight MMS employees who accepted lavish gifts, partied and - in some cases - had sex with employees from the energy companies they regulated. An investigation cited a "culture of substance abuse and promiscuity" involving employees in the agency's Denver office.

MMS workers were given upgraded ethics training.