With oil no longer gushing into the Gulf of Mexico, Bill Nelson is worried about the "toxic brew" that may lurk in the depths way below the surface.
So the Democratic U.S. senator from Florida is co-sponsoring a bill that would make it tougher for dispersants to be used in the fight against any future oil spill.
BP and the Coast Guard teamed up to use about 1.8 million gallons of a dispersant to combat the largest oil disaster in the nation's history. They attacked the oil on the surface with aerial assaults and pumped a plethora of dispersants at the source of the leak a mile underwater.
That usage came despite a lot of unknowns on what the effects of the dispersants - designed to break up the oil and keep it from floating ashore - might have on marine life.
"The public sense is that there is a winding down because no more oil is gushing,'' Nelson said at a news conference this morning in downtown Tampa. "But the real potential danger still lurks, because there is a toxic brew that is underneath the surface that you cannot see.''
Adding to the quandary, Nelson said, is that the Environmental Protection Agency allows the oil company and the company that makes the dispersant to do their own safety checks.
"That is like the fox guarding the henhouse,'' he said. "That's like leaving it to the Chinese government to determine the amount of lead in the toys that were sent and then became toxic to children.''
His bill would amend the Federal Water Pollution Control Act and allow oversight of the dispersant testing by people other than the companies involved.
"It comes down to the health and safety of the public,'' Nelson said. "There is a reason for disclosure ... Now we are faced with the big unknown."
The senator said he made it a point to order fresh Gulf grouper when he had dinner in Orlando on Sunday evening. And he noticed that no one else in the restaurant was ordering it.
"There is this fear that the seafood out of the Gulf is tainted,'' he said.
The same day that Nelson introduced his bill in the Senate, a new federal study of chemical dispersants was released that shows that when mixed with oil, the dispersant is less toxic to aquatic life than oil alone.
The study also shows that when mixed with oil, the dispersant used in the Gulf, Corexit 9500A, is no more or less toxic than oil mixtures with other chemical dispersants approved for use in oil spills.
The EPA released the study results today as the Obama administration defended itself against assertions that officials allowed oil giant BP to use excessive amounts of chemical dispersants whose threat to sea life remains unknown.
Congressional investigators charge that the Coast Guard routinely approved BP requests to use thousands of gallons per day of Corexit despite a federal directive to use the chemical sparingly.
The Coast Guard approved 74 waivers over a 48-day period after the EPA order, according to documents reviewed by the investigators. Only in a small number of cases did the government scale back BP's request.
EPA Administrator Lisa Jackson said in a statement that officials have long acknowledged use of dispersants presents environmental trade-offs. The agency took steps to ensure that other response efforts were used instead of dispersants and dramatically cut dispersant use in late May, she said.
Dispersants were last used July 19, four days after a temporary cap was placed on the leaking well, and dispersant use dropped by 72 percent from peak volumes following a joint EPA-U.S. Coast Guard directive to BP in late May, Jackson said.
While the chemical dispersant was effective at breaking up the oil into small droplets so that it could be more easily consumed by bacteria, the long-term effects to aquatic life are unknown. That environmental uncertainty has led to several spats between BP and the government over the use of dispersants on the water's surface and deep underwater when oil was spewing out of the well.
That is what has most concerned Nelson and Bob Weisberg, a professor at the University of South Florida's College of Marine Science.
Weisberg has been one of the researchers at the forefront of the educational community's investigation into the oil's impact on the Gulf. He said that the R/V Weatherbird II will take another trip into the Gulf later this week or early next week for more research.
USF was the first group to find that there were huge quantities of oil well below the surface of the Gulf.
This latest trip will head into the northern Gulf to look for subsurface oil where scientists already have found it, Weisberg said. Researchers will also check previously untainted waters of the west Florida continental shelf to see if the oil has had an impact there, he added.
Nelson said that the National Oceanic and Atmospheric Administration has been "slow at the switch'' in getting an investigation under way to see what is happening below the surface of the Gulf waters.
He also had harsh words for Florida lawmakers who ignored Gov. Charlie Crist's call for letting voters decide if they wanted to ban near-shore oil drilling.
"Those legislators ought to have the political tar beat out of them,'' the senator said.