Take a look at this piece from today's Houston Chronicle: Offshore accidents bring few penalties: Federal inspectors collect only 16 fines in nearly 400 investigations
The story's headline and lede focus on the penalties, but the body of the report notes that very few reported accidents were even investigated. The story says:
The [Minerals Management Service] rules require investigations of all blowouts.
Yet, the Chronicle could find no proof that the agency did any formal investigation in at least nine of 28 blowouts reported to the MMS in the last five years.