History Today: The deadly Deepwater Horizon blast that led to a massive oil spill

On April 20, 2010, the Deepwater Horizon oil rig, which was drilling at the Macondo Prospect in the Gulf of Mexico, exploded and later sank. The disaster killed 11 workers and led to the largest oil spill ever recorded in marine drilling.

Also, on this day in 1999, two students opened fire at Columbine High School near Denver, Colorado, killing twelve classmates and a teacher, and injuring twenty-three others before ending their own lives. The tragedy led to a national debate in the United States about gun laws and school safety, and led to an extensive inquiry into the shooters’ motives.

If you are a history geek who loves to learn about important events from the past, Firstpost Explainers’ ongoing series, History Today, will be your one-stop destination to explore key events.

Explosion on the Deepwater Horizon oil rig

A blast and fire broke out on the Deepwater Horizon oil rig in the Gulf of Mexico, about 50 miles off the Louisiana coast, killing eleven people. It went on to become the largest oil spill in the history of marine drilling.

At the time, the rig was finishing work on an exploratory well for BP, the British oil company. Over the next three months, around 4.9 million barrels, or about 780 million litres, of crude oil spilt into the sea before the well was sealed.

The incident began when a burst of natural gas surged up a riser pipe to the platform, leading to explosions and a huge fire. Of the 126 people on the rig, which was nearly 400 feet long, eleven died and seventeen others were badly injured.

The fire raged for over a day before the Deepwater Horizon, built in 2001 for $350 million, sank on April 22 in water about 5,000 feet deep.

Over the following weeks, several methods were tried to stop the leak, as thousands of barrels of oil poured into the Gulf daily.

On July 15, BP said it had managed to put a temporary cap on the well. On September 19, after injecting cement to block it for good, the US government announced the well was sealed.

In January 2011, a national commission investigating the disaster called it “foreseeable and preventable,” blaming it on “human error, engineering mistakes and management failures,” as well as ineffective government oversight.

In March 2012, BP agreed to pay at least $7.8 billion to settle claims brought by the plaintiffs’ steering committee, which represented many of the spill’s victims.

Later that year, in November, BP made a deal with the US Department of Justice to plead guilty to fourteen criminal charges. These included eleven counts of felony manslaughter and breaches of the Clean Water and Migratory Bird Treaty Acts.

The deal included over $4.5 billion in fines and penalties. Around $1.26 billion went to a discretionary fund under the DOJ, $2.4 billion to the National Fish and Wildlife Foundation, and $350 million to the National Academy of Sciences.

Columbine High School shooting

On April 20, 1999, a shooting at Columbine High School in Littleton, Colorado, just south of Denver, led to the deaths of 14 people, including the two teenage attackers.

It became one of the deadliest school shootings in the United States. The attackers were Eric Harris, 18, and Dylan Klebold, 17.

That morning, they entered their school in Jefferson County armed with pistols, semiautomatic weapons and homemade explosives.

By 11:35 am, Harris and Klebold had taken the lives of 12 other students and a teacher, while injuring 23 others. Soon after midday, both turned their weapons on themselves and died by suicide.

The incident led to a countrywide discussion on gun laws and how to keep schools safe. A large-scale investigation was also launched to understand what led the two teens to commit such violence.

In the aftermath, there were reports that the two had targeted specific groups, including athletes, ethnic minorities and Christians.

Speculation also emerged that the attackers were part of a group known as the “Trenchcoat Mafia,” a circle of students seen as outsiders, said to be interested in Goth culture.

Some pointed to violent video games and music as possible influences. However, no clear evidence was ever found to support any of these ideas.

Years later, in 2025, one of the students wounded in the attack died due to complications from those injuries. Her death was ruled a homicide, bringing the total number of victims to 14.

When the shooting shocked the country, many questioned the delay in the police response.

Although the attack had ended around midday, law enforcement officials, worried there were more shooters or explosives, held back from entering the scene for several hours. During this time, some victims died from their injuries.

On a bigger level, the Columbine shooting reshaped the conversation around school safety. Schools across the US began investing in more private security and installing metal detectors in an attempt to prevent further tragedies.

This Day, That Year

1812: George Clinton, the fourth vice president of the United States, passed away in Washington at the age of 72. He was the first vice president to die while still holding office.

1889: Adolf Hitler, the dictator of Nazi Germany, was born.

1972: The Apollo 16 lunar module with astronauts John W. Young and Charles M. Duke Jr. on board touched down on the moon.

1980: Fidel Castro declared the start of the Mariel Boatlift, allowing Cubans to leave for the United States.

1986: Michael Jordan of the Chicago Bulls scored 63 points in a playoff match against the Boston Celtics, setting a new record for points in an NBA postseason game.

1997: Inder Kumar Gujral was officially chosen as India’s Prime Minister-designate by the United Front Parliamentary Group.

2021: Derek Chauvin, a former police officer in Minneapolis, was found guilty of murder and manslaughter in the death of George Floyd. He was later sentenced to 22 and a half years in prison.