Corexit was used in unprecedented quantities during the 2010 Deepwater Horizon oil spill in the Gulf of Mexico and became the largest use of such chemicals in the United States . In addition to spraying the dispersant onto the surface slick , it was used in an untested , off-label manner when BP injected it at the broken well-head , roughly 5,000 feet below the surface . Researchers continue to examine the effects and effectiveness of Corexit . Studies have so far indicated that the dispersant is toxic to marine life . Corexit has been shown to exert a synergistic effect when mixed with oil , increasing its toxicity
Deepwater Horizon oil spill
Deepwater Horizon oil spill
Corexit