The Deepwater spill was caused by an explosion on the BP-operated Deepwater Horizon oil drilling rig—located around 41 miles off the Louisiana coast—on April 20, 2010, which resulted in the deaths of 11 workers.
The rig subsequently sank and more than four million barrels of oil gushed out of the damaged Macondo well over the course of 87 days until the leak was finally capped, according to the Environmental Protection Agency.
…The spill was the largest in marine history, releasing around 795 million liters (210 million gallons) of oil into the Gulf of Mexico with slicks covering an estimated area of 57,500 square miles. The disaster caused extensive environmental damage and forced the closure of vast stretches of the Gulf to fishing operations.
…The “toxic extent” of the spill could [be] up to 30 percent greater than what previous satellite data has suggested, leaving a footprint which stretched from Florida’s Gulf Coast, to the shores of Texas and the Florida Keys.
…”We found that the oil spill extended beyond the satellite footprint, reaching areas which were considered non-contaminated such as the West Florida shelf and Texas shores. A part of the invisible portion that extended beyond the satellite footprint was toxic to marine life,” the authors said.
According to the study, toxic chemicals known as polycyclic aromatic hydrocarbons may still be present in water for days or even weeks after satellites can no longer detect an oil slick.