BP’s chief executive Bob Dudley recently boasted in an interview, “The Gulf has bounced back really well. And I’d like to think that we played a big role.”

The more than 900 bottlenose dolphins that have died since the spill might indicate otherwise. National Oceanic and Atmospheric Administration is still investigating the ongoing wave of dolphin deaths and the agency has explicitly stated that it is considering the oil spill as a potential cause.

Here’s what we know about the ongoing dolphin deaths:

The deaths are concentrated in states closest to the Deepwater Horizon. Louisiana, ground zero for spill impacts, has also seen the largest number of dead dolphins. Stranding rates in Mississippi and Alabama remain elevated, while deaths in the less-affected Florida Panhandle have returned to normal historical levels.

Louisiana, ground zero for spill impacts, has also seen the largest number of dead dolphins. Stranding rates in Mississippi and Alabama remain elevated, while deaths in the less-affected Florida Panhandle have returned to normal historical levels. An in-depth study of 32 dolphins in one particularly heavily-oiled area of the Louisiana coast found the animals there were seriously ill with symptoms indicating oil exposure . Specifically, the dolphins in the study were underweight, anemic, had low blood sugar, and some had symptoms of liver and lung disease . Half the dolphins also had abnormally low levels of the hormones that help with stress response, metabolism, and immune function.

. Specifically, the dolphins in the study were underweight, anemic, had low blood sugar, and some had symptoms of liver and lung disease Half the dolphins also had abnormally low levels of the hormones that help with stress response, metabolism, and immune function. Roughly a quarter of the dolphins tested appear to have died from a bacterial infection . Teri Rowles, the coordinator of NOAA’s National Marine Mammal Health and Stranding Response Program, points out that the presence of the Brucella bacteria does not rule out the oil spill, saying, “Severe environmental stress, including from exposure to oil, could have reduced the animals’ ability to fight infection.”

Teri Rowles, the coordinator of NOAA’s National Marine Mammal Health and Stranding Response Program, points out that the presence of the Brucella bacteria does not rule out the oil spill, saying, “Severe environmental stress, including from exposure to oil, could have reduced the animals’ ability to fight infection.” Stillborn dolphin calves have been found in high numbers every spring since the oil disaster. Infant dolphins were found dead at almost four times historical rates during the first four months of 2013.

Infant dolphins were found dead at almost four times historical rates during the first four months of 2013. NOAA has ruled out the two most common causes of previous dolphin die-offs. Brucella has never before been associated with a wave of deaths in any marine mammal in the United States.

More than three years after the well was capped, the disaster’s effects appear to still be unfolding—despite BP’s slick public relations campaigns. Scientists say it will still be many years, even decades, before we understand the true impact of the roughly four million barrels of crude oil unleashed on the ecosystem of the Gulf of Mexico.

Help protect dolphins in the Gulf of Mexico—urge the Secretary of Commerce to make sure oil spill money is used to restore dolphin habitats.