The Deepwater Horizon Oil Spill, 5 Years Later

— -- Five years after the explosion of BP's Deepwater Horizon rig that killed 11 people and triggered the greatest oil spill in U.S. history, the company is waiting for a federal court to decide just how much it will have to pay in fines for violating the Clear Water Act.

After months of litigation, the final ruling is expected out this summer. It will set a penalty for the company ranging from $1,100 to $4,300 per barrel -- for each of the 3.19 million barrels spilled during the 87 days before the well was capped.

Last September, in the first phase of the Clean Water Act trial, the U.S. District Court for Eastern Louisiana charged BP with "gross negligence," in regards to equipment and safety precautions.

"BP was reckless," the ruling stated.

If the gross negligence charge stands, BP could the face the maximum penalty per barrel of oil spilled.

In a second phase of the litigation related to the cleanup, the judge did not find the company grossly negligent and refrained from ruling on a lesser charge of "negligence."

"We have argued that not only were our actions that night not grossly negligent, but that there are several mitigating factors that need to be taken into account when we are ultimately determining the penalty," BP's spokesperson, Geoff Morrell, told ABC's Matt Gutman in a one-on-one interview this week.

Factors such as the fact that the company committed $1 billion to early restoration projects, which BP argues should be taken into account when determining the penalty. To date, BP has paid nearly $30 billion for clean-up, initial settlements and environmental studies.

But many on the ground believe that money only covers the first mile in a marathon race for restoration of the Gulf.

"Clean-up isn't restoration," argued Alisha Renfro, a staff scientist for National Wildlife Federation's Mississippi River Delta Restoration Campaign. "You don't get a cookie for doing what you are required to do by law. Clean-up is absolutely essential and it is the first step, but this continues and will continue to be a problem for years to come."

While some of the worst fears from the spill years ago were never realized, scientists like Renfro point to issues like erosion, which has been a problem in the Gulf from years, but found by some studies to be dramatically hastened in the months following the spill. According to scientists from the University of Florida, the spill more than doubled the rate of erosion for 18 months along the edge of marshlands after the oil killed grasses and roots that hold the sediment together.

The science is ongoing.

"We are looking at it. The federal government and state governments are looking at whether or not the exposure to oil in any way hastened the erosion of barrier islands or marshes," Morrell said.

The official report on the long-term environmental impacts of the spill is still confidential and not expected to be released for another year or so. Still, it is indirect consequences of what happened five years ago that could influence the court's final decision.

Editor's Note: The number of barrels of spilled oil referenced in this story was changed to reflect the exact number of barrels the judge has stated will be used for calculating damages for Clean Water Act violations.