One of the worst environmental catastrophes in American history occurred on April 20, 2010, when the Deepwater Horizon oil rig exploded. Operating in the Macondo Prospect, a deep-sea oil reservoir almost a mile below the ocean's surface, the floating offshore oil rig was leased by BP and was situated about 41 miles off the coast of Louisiana. An estimated 4.9 million barrels of oil leaked into the Gulf of Mexico during the 87-day spill, with the incident claiming the lives of 11 workers and injuring 17.

But the seeds of the disaster were sown well before the explosion. On the 8th of April, engineers noticed unexpected pressure abnormalities while circulating drilling fluids, early indications of well instability. Then on April 19, during cementing operations, BP opted for a faster, more cost-effective design with fewer centralizers than advised, a risky decision that jeopardized the cement's ability to create a trustworthy seal. Internal tests conducted by Halliburton even indicated that this design might not work, but nothing was done about it.

To make sure the well wouldn't leak, the crew tested the seal's integrity using a negative pressure test on the morning of April 20. The findings, which displayed erratic pressure readings, were unclear. Supervisors, however, decided the test was successful and continued. Much lighter seawater was then used to fill the well in place of the heavy drilling mud, which controlled the well's pressure. These errors would turn out to be deadly, as the seal failed and created an opportunity for high-pressure hydrocarbons to rise up the wellbore.