The 2010 BP Deepwater Horizon oil spill has become the defining image of the environmental perils associated with offshore oil drilling. However, well away from the TV cameras and public outrage, a lesser-known oil spill is going on right now and it has the potential to become the one of the worst in US history.

The "Taylor leak" started hemorrhaging oil into the Gulf Of Mexico around 16 kilometers (10 miles) off the coast of Louisiana in 2004, after Hurricane Ivan caused a mammoth submarine landslide. Some 14 years on, with just nine of the 25 leaking wells plugged, it’s still spewing tens of thousands of gallons of oil into the Gulf every single day.

The quantities of oil are still a matter of contention and secrecy, but most estimates suggest it will become one of the worst offshore disasters in US history, as The Washington Post reports.

A big investigation by the Associated Press (AP) in 2015 found that the oil leak was far worse – over 20 times worse in terms of oil quantity – than Taylor Energy had originally reported. A recent AP report has said that a court filing submitted by Federal government lawyers suggest between 37,000 to 113,000 liters (8,140 to 24,860 gallons) of oil is leaking daily from multiple wells around a drilling platform. The federal lawyers cite a report made by a scientist who studied satellite images of the area and sampled oil at the site.

The Deepwater Horizon oil spill released 134 million gallons of oil into the Gulf of Mexico over 87 days. As a direct result of oil contamination, NOAA scientists concluded that Deepwater Horizon killed thousands of marine mammals and sea turtles, on top of contaminating their habitats.

“The Taylor leak is just a great example of what I call a dirty little secret in plain sight,” John Amos, President of SkyTruth, an environmental watchdog group that has monitored the slicks by satellite, told AP in 2015.

Remarkably, the public only found out about the leak in 2010 when people investigating the Deepwater Horizon oil spill noticed an odd oil spill in satellite images of the area. Even after it came to light, they downplayed the spill’s scale and claimed that photos of the leak were misleading.

Taylor Energy is now defunct. Four years after the company’s founder died in 2004, the company agreed to sell off all its energy assets to Samsung C&T Corporations and Korea National Oil Corporation. A $666 million trust was set up to pay for leak response work, however, there is now a legal dispute over the remaining $423 million, which has been left unspent.

Meanwhile, the oil continues to flow.