The document summarizes the Deepwater Horizon oil spill that occurred when the Macondo well blew out on BP's leased Deepwater Horizon oil rig. It killed 11 people and spilled millions of barrels of oil into the Gulf of Mexico over 87 days. The spill was caused by several factors including well design issues, failed safety systems, organizational and risk management failures at BP, outdated government oversight and regulations, and other contributing external factors. The document analyzes BP and industry strategic risk factors and decision theories that may have led to the accident through an overemphasis on growth and profits without adequate risk mitigation. It concludes with lessons learned about the need for industry and regulatory changes to improve safety practices for offshore drilling.