What Happened at the Deepwater Horizon Disaster?

The April 20, 2010 explosion of the Deepwater Horizon, some 41 miles off the coast of Louisiana in the Gulf of Mexico, unleashed one of worst environmental disasters in history.  By some estimates, as many as 5 million barrels of oil would flow into the pristine Gulf waters before BP’s Macondo well would be capped in  July. 

The blowout of the Macondo well and the ensuing explosion of Transocean’s Deepwater Horizon drilling rig—which killed 11 rig workers and injured scores more—was not an “accident” in the ordinary sense of the word.  It was a foreseeable and completely avoidable disaster of epic proportion.  While many corporate entities contributed to the explosion of the Deepwater Horizon and its aftermath, its principal cause was the culmination of a multitude of bad choices and careless, even reckless, acts and omissions by BP, Transocean, and Halliburton, whose corporate cultures for years had put profits over worker safety and concern for the environment.  According to Chapter 4 of the National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling report, released on January 6, 2011:

“The well blew out because a number of separate risk factors, oversights, and outright mistakes combined to overwhelm the safeguards meant to prevent just such an event from happening. But most of the mistakes and oversights at Macondo can be traced back to a single overarching failure—a failure of management. Better management by BP, Halliburton, and Transocean would almost certainly have prevented the blowout by improving the ability of individuals involved to identify the risks they faced, and to properly evaluate, communicate, and address them.”

Because of this engrained corporate culture, in the evening hours of April 20 a cascade of failures occurred that resulted in an uncontained blowout and ended two days later with the sinking of the Deepwater Horizon some 5000 feet to the Gulf floor.  These failures, all avoidable, were caused by carelessness and inaction both before and at the time of the blow-out and resulting explosions.  There would be the failure of the blowout preventer; the failure of warning and alarm systems; the failure of emergency shut-off systems; and the failure of the rig disconnect system, among others.  Some safety systems were effectively disabled by prior decisions to deactivate automated triggering, while others failed because of the inaction of workers who had not been properly trained to react promptly and decisively to the events that unfolded that evening. 

The systemic failures that culminated in the blowout and its aftermath were set in place long before April 20, 2010.  These companies all operated for years with the singular mission of getting wells up and producing oil as fast as possible—relegating worker safety behind the pursuit of profits.  Safety planning and implementation takes time, and time is money.  The threat to the environment and ecosystems that support fisheries and the pristine beaches of the Gulf were of secondary concern.  As stated by Bob Graham, Co-Chair of the National Commission on the BP Deepwater Horizon Oil Spill and Offshore Drilling,  “The Commission’s findings only compound our sense of tragedy because we know now that the blowout of the Macondo well was avoidable. This disaster likely would not have happened had the companies involved been guided by an unrelenting commitment to safety first.”

Decisions made and protocols set in place long before the Macondo blowout set the stage for the Gulf disaster.  The responsible companies did not provide their crews with the training and tools needed to deal with a major blowout.  Workers were instilled with a fear of activating emergency “well control” measures that would delay the ultimate goal of getting the well finished, while procedure manuals warned workers not to act prematurely, effectively paralyzing decision-making when prompt and decisive action was critical.  Automated safety systems had been disabled, thereby requiring workers to recognize the signs and symptoms of the impending blowout and affirmatively decide whether and when to sound an alarm and disable the well—knowing that such a decision would delay drilling, set back the work schedule, increase costs and decrease corporate profits.   

Examination of the events that unfolded on April 20 reveals a series of missteps and failures that culminated in the blowout and its aftermath.  Among them:

  • Signs of increasing well pressures and leaks were missed, misunderstood or ignored.
  • Cementing at the base of the well was carried out with a woefully inadequate number of ‘Centralizers”, which compromised the integrity of the cementing operation that secures the well pipe at the well’s base.
  • The cement slurry was not properly tested before it was used.
  • Pre-approved cementing specifications were abandoned and substituted with more risky methods without consideration of safety.
  • BP chose to employ a 500 foot column of cement in the well, directly contrary to its own guidelines that specified a 1000 foot minimum above the hydrocarbon zone—thereby compromising safety and increasing the risk of blowout.
  • Drilling fluid or “mud” was removed too quickly and prematurely and test results during the operation were misinterpreted or ignored.
  • Increasing gas pressures and other signs of impending disaster were misunderstood or ignored.
  • The “fail-safe” Blowout Preventer in fact failed, due, among other reasons, to shoddy and haphazard maintenance and inspections in the years prior to the moment when it was called upon to perform the critical safety function for which it was singularly designed.
  • Once the blowout occurred, alarms were not sounded in a timely manner, in part because automated systems had been disabled.
  • The EDS or Emergency Disconnect System, which is designed to jettison the rig from the well malfunctioned, thereby keeping the rig tethered to the explosive well and sealing the fate of the Deepwater Horizon and those on board.  

The events of April 20, 2010 were, in a very real sense, predictable.  All three of the principal wrongdoers—BP, Transocean and Halliburton—had a history of taking risks that compromise worker safety and threaten the environment.  According to the National Commission, “. . .the Macondo blowout was the product of several individual missteps and oversights by BP, Halliburton, and Transocean, which government regulators lacked the authority, the necessary resources, and the technical expertise to prevent.”  Also,

“What we. . .know is considerable and significant: (1) each of the mistakes made on the rig and onshore by industry and government increased the risk of a well blowout; (2) the cumulative risk that resulted from these decisions and actions was both unreasonably large and avoidable; and (3) the risk of a catastrophic blowout was ultimately realized on April 20 and several of the mistakes were  contributing causes of the blowout.”

 Against this backdrop, it should come as no surprise that since 2008, nearly three of every four incidents that triggered federal safety investigations on deepwater drilling rigs in the Gulf of Mexico have been on Transocean rigs. The Deepwater Horizon itself had been the subject of six "incidents of noncompliance"—the term used by the U.S. Mineral Management Services (MMS) for failure to comply with federal regulations and standards.   The most serious incident occurred on July 16, 2002, when the rig was shut down because required pressure tests had not been conducted on parts of the rig's blowout preventer.  In CNN interviews, workers described a corporate culture of cutting staff and ignoring warning signs.  Rig survivors understood that raising safety concerns could mean getting fired.  Workers reported that BP routinely cut corners and pushed ahead despite concerns about safety, which is underscored by the company’s ignoble distinction of having had, from 2000 through 2009, more spills than any other oil company—logging 23 spills of 50 barrels or more.

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