The Deepwater Horizon spill was leaking 5,000 barrels a day
| The Deepwater Horizon spill was leaking 5,000 barrels a day | |
|---|---|
| FALSE | |
| "The damaged BP well in the Gulf of Mexico was leaking about 1,000 barrels of oil a day, later revised to about 5,000 barrels a day." | |
| Domain | Science & Environment |
| Tactic | Statistical & Evidentiary Distortion |
| Era | Current |
| First seen | 2010 |
| Origin | Official estimates issued by BP and US government agencies in the weeks after the April 20, 2010, explosion of the Deepwater Horizon drilling rig |
| Last reviewed | 2026-10-27 |
| Further reading: books on Science & Environment | |
The claim that the Deepwater Horizon spill was leaking 5,000 barrels a day was the official estimate for several weeks after the Deepwater Horizon drilling rig exploded in the Gulf of Mexico on April 20, 2010, killing eleven workers. The first estimate was 1,000 barrels a day. Independent scientists analyzing video of the gushing well quickly concluded that the true rate was many times higher. A government scientific team later estimated that the well had initially released about 62,000 barrels a day. Over 87 days, the spill released roughly 4 million barrels or more, making it the largest marine oil spill in US history. BP later pleaded guilty to a criminal charge of obstructing Congress over its statements about the flow rate.
The claim
On April 24, 2010, the US Coast Guard and BP said that oil was leaking from the well at about 1,000 barrels a day. On April 28 the National Oceanic and Atmospheric Administration raised the estimate to about 5,000 barrels a day, a figure that was repeated for weeks. BP's chief executive, Tony Hayward, said in mid-May that the amount of oil and dispersant was "relatively tiny" compared with the size of the ocean.
What the evidence shows
- Independent analysis. In May 2010 scientists including Steve Wereley of Purdue University used video of the leak released by BP to estimate the flow rate. Their estimates were around 70,000 barrels a day or more, many times the official figure.
- Flow Rate Technical Group. The US government established a team of scientists to estimate the flow. Its estimates rose repeatedly through May and June. The final government estimate, released in August 2010, was that the well had released about 62,000 barrels a day at the start, declining to about 53,000 barrels a day before it was capped, for a total of about 4.9 million barrels. In 2015 a federal judge, for the purpose of calculating penalties, determined that about 3.19 million barrels had been discharged, after accounting for oil collected and other factors.
- Why it mattered. The flow rate determined how many resources were needed for the response, how much dispersant was used and how penalties would be calculated under the Clean Water Act, which are based partly on the amount spilled.
Legal consequences
In 2012 BP pleaded guilty to fourteen criminal counts, including eleven counts of felony seaman's manslaughter for the deaths of the workers and one count of obstruction of Congress for misrepresenting the flow rate in its responses to Congress. It agreed to pay about $4 billion in criminal penalties. In 2015 BP agreed to a settlement of about $20.8 billion with the federal government and Gulf states, then the largest environmental settlement in US history. A BP executive charged with obstruction related to flow rate estimates was acquitted in 2015. BP's total costs from the disaster exceeded $60 billion.
Why it matters
The low early estimates illustrate how initial figures in a disaster, especially when they come from the responsible party, can understate the problem. Because the 5,000-barrel figure was presented by government agencies, it carried authority. The independent scientists who challenged it, using publicly available video, played an important role in revealing the true scale. The episode also showed the value of making raw data, such as video of the leak, publicly available.
Lessons for readers
- Treat early estimates in disasters as provisional, especially when they come from parties with a financial interest.
- Ask how an estimate was produced and whether independent experts agree.
- Public access to raw data allows independent checking.
- Large numbers can be minimized by comparing them with something even larger, such as "a very big ocean."
- Figures used for penalties can create incentives to minimize.
See also
- Volkswagen clean diesel
- Exxon did not know fossil fuels would cause global warming
- Flint's water was safe to drink
- Doubt Is Their Product (Michaels)
Sources
- National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling, Deep Water: The Gulf Oil Disaster and the Future of Offshore Drilling (2011).
- Marcia K. McNutt et al., "Review of flow rate estimates of the Deepwater Horizon oil spill," Proceedings of the National Academy of Sciences 109, no. 50 (2012).
- US Department of Justice, "BP Exploration and Production Inc. Agrees to Plead Guilty to Felony Manslaughter, Environmental Crimes and Obstruction of Congress," press release, November 15, 2012.
- In re: Oil Spill by the Oil Rig "Deepwater Horizon", US District Court for the Eastern District of Louisiana, findings on quantification (January 2015).