Research entry · Not admitted

Deepwater Horizon Macondo

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Research dossier, timeline and source context. The original research material remains available for inspection.

On April 20, 2010, a loss of well control at BP's Macondo prospect in the Gulf of Mexico triggered a blowout, explosion, and fire aboard the drilling rig Deepwater Horizon, killing 11 workers. The rig sank two days later, and the ruptured wellhead released oil into the Gulf for 87 days before it was capped, in what investigators concluded was the largest accidental marine oil spill in U.S. history. Federal and independent investigations attributed the blowout to a combination of failed cement work, misread pressure tests, and a malfunctioning blowout preventer, implicating BP as well contractors Transocean and Halliburton.

A federal court's 2015 finding on discharge volume and each company's comparative share of fault is a distinct legal outcome from the broader public narrative of the spill's causes, and the two should not be collapsed into one figure. The court's barrels-released and fault-percentage findings set the basis for civil penalties under the Clean Water Act; they resolve the litigated apportionment of liability among the companies involved, not a complete technical or regulatory account of why the well failed.

Temporal bounds

Core casualty/spill: April–September 2010. Technical investigations: 2010–2016. Civil/criminal adjudication: 2012–2016. Restoration implementation: 2016–2026 and ongoing.

Questions in the research record

C-1 — "The cement caused the blowout" is both supported and too simple · question / dispute
C-2 — Technical causation vs comparative legal fault · question / dispute
C-3 — "BP caused it" vs "BP alone caused it" · question / dispute
C-4 — Halliburton's guilty plea vs Halliburton's causal role · question / dispute
C-5 — BP manslaughter plea vs civil gross negligence · question / dispute
C-6 — Transocean Clean Water Act plea vs 30% comparative fault · question / dispute
C-7 — "Regulatory failure caused it" is too broad · question / dispute
C-8 — BOP failure: last line of defense vs root cause · question / dispute
C-9 — 5 million vs 4.0 million vs 3.19 million barrels · question / dispute
C-10 — Environmental-restoration dollars vs spill volume / legal penalty · question / dispute
C-11 — BP internal report vs later independent/judicial findings · question / dispute

Not established on this record

Boundary

"BP caused Deepwater Horizon" is not specific enough to be a governed causal claim.

semantic trap / refusal

Boundary

Technical failure ≠ operational failure ≠ organizational failure ≠ regulatory failure ≠ legal fault allocation.

semantic trap / refusal

Boundary

"The cement failed" is stronger than "unstable cement caused the blowout."

semantic trap / refusal

Boundary

"Halliburton pleaded guilty" needs the offense.

semantic trap / refusal

Boundary

"Transocean pleaded guilty" also needs the offense.

semantic trap / refusal

Boundary

"Five million barrels spilled" can refer to an early/then-current estimate.

semantic trap / refusal

Boundary

"4 million barrels" and "3.19 million barrels" are not contradictory.

semantic trap / refusal

Boundary

An accident-investigation report is not a civil judgment.

semantic trap / refusal

Boundary

A civil comparative-fault percentage is not a scientific decomposition of physical causation.

semantic trap / refusal

Boundary

A criminal guilty plea is not a comparative-fault allocation.

semantic trap / refusal

Boundary

A consent decree resolving environmental/economic claims is not the same source as the earlier Phase One gross-negligence/fault judgment.

semantic trap / refusal

Boundary

A regulator violation notice is not identical to a criminal conviction or tort finding.

semantic trap / refusal

Boundary

BP's internal report, Transocean's internal report and Halliburton's statements are first-party investigative positions, not neutral institutional findings.

semantic trap / refusal

Boundary

The National Commission, BOEMRE JIT, USCG, CSB, flag state, district court and corporate investigations had different mandates.

semantic trap / refusal

Boundary

"Regulations caused the spill" is too broad.

semantic trap / refusal

Boundary

"The BOP failed" is not one mechanism.

semantic trap / refusal

Boundary

"Oil spilled for 87 days" is a duration summary, not an assertion that flow was constant or that every barrel reached the Gulf uncollected.

semantic trap / refusal

Boundary

Natural-resource restoration dollars are not a direct measure of all ecological damage, private economic loss, criminal penalties or total corporate cost.

semantic trap / refusal

Record provenance

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Projection axes

Postureresearch

Source kindresearch_template

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Record identifier: research:demo-corpus-twelve:deepwater-horizon-macondo-demo-corpus-dossier-v0-1
Posture: research
Source kind: research_template
Lifecycle: not recorded
Source footprint: not supplied to this presentation
Capture associations: not evaluated here
Unresolved capture identity: not evaluated here
Truth: not a finding of this renderer
Authenticity: not inferred from source or capture presence
Research profile: Demo Corpus
Artifact kind: dossier
Source candidates: 20

CHECK is inspection, not a truth badge. Source presence ≠ support; capture association ≠ authenticity; rendering ≠ admission.

Deepwater Horizon Macondo

Temporal bounds

Questions in the research record

Not established on this record

Read with sources

Selected sources (20)