Reuters: Millions of gallons/liters of oil have spewed into the Gulf of Mexico since an April 20 explosion on a drilling rig triggered the worst spill in U.S. history. Below is a timeline of the disaster and its impact. April 20, 2010 – Explosion and fire on Transocean Ltd’s drilling rig Deepwater Horizon licensed to BP Plc; 11 workers are killed. The rig was drilling in BP’s Macondo project 42 miles southeast of Venice, Louisiana, beneath about 5,000 feet of water and 13,000 feet under …