Deepwater Horizon Accident Investigation Report
TL;DR
8 cascading failures killed 11: negative pressure test screamed warning for 3 hours, crew called it 'bladder effect'.
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BP's internal investigation documents how multiple safety barriers failed sequentially because warning signals were rationalized away—a pattern that reveals how redundancy systems collapse when alarm-call responses break down.
Key Findings from Bly (2010)
- Eight critical factors identified; no single cause but cascading failures across multiple parties (BP, Transocean, Halliburton)
- Negative pressure test showed 1,400 psi of well pressure for three hours—crew dismissed it as 'bladder effect'
- Cement barrier failed to seal hydrocarbons; nitrified foam cement formulation was flawed and inadequately tested
- Blowout preventer—last line of defense—failed to activate properly
- Investigation produced 25 recommendations covering BOPs, well control, cement testing, and personnel competency
- BP pleaded guilty to 14 federal charges (12 felonies) and paid $4.5 billion in penalties
- 'Eerie similarities' noted to BP's 2005 Texas City refinery disaster—same pattern of ignored warnings