On April 20, 2010, BP’s Deepwater Horizon well exploded, killing eleven workers and gushing over 200 million gallons of oil into the Gulf of Mexico. Now, BP says it’s ending the “active cleanup.” But the US Coast Guard and conservation groups say the job is not yet done.On April 20, 2010, BP’s Deepwater Horizon well exploded, killing eleven workers and gushing over 200 million gallons of oil into the Gulf of Mexico. Now, BP says it’s ending the “active cleanup.” But the US Coast Guard and conservation groups say the job is not yet done.