A blowout at the 
Ixtoc I oil well in the southern 
Gulf of Mexico causes at least 600,000 tons (176,400,000 gallons) of oil to be spilled into the waters, the worst 
oil spill to date. Some estimate the spill to be 428 million gallons, making it the largest unintentional 
oil spill until it was surpassed by the 
Deepwater Horizon Oil Spill in 2010.