Isaac's high winds and rains, they speculate, could also stir up remnant crude oil from the BP's Deepwater Horizon spill -- exposing more residents and wildlife to its potentially toxic effects.
"This is another disaster on top of the hurricane that we're going to have to deal with," Garret Graves, chairman of Louisiana's Coastal Protection and Restoration Authority, told The Huffington Post. "The threat is not insignificant."
Up to 1 million barrels of oil are estimated to remain in the Gulf of Mexico. That oil remains, Graves said, because BP has failed to clean it all up in the more than two years since the tragedy. "That's four to five times the oil that was spilled with the Exxon Valdez," he added.
In total, an estimated 4.9 million barrels of oil spewed into the Gulf of Mexico when the offshore rig exploded on April 20, 2010. As HuffPost reported on the spill's two year anniversary, some people, particularly children, may still be dealing with chronic coughs, headaches and other effects of exposure to contaminated air, water and seafood.
Graves fears the hurricane could spawn another wave of similar health issues.
He also noted that hurricane clean up could be complicated by the oil. Debris from a destroyed home, for example, could become hazardous waste and need special, more expensive disposal, rather than simply going to the landfill.
"The frustrating thing is that this could all have been entirely prevented," said Graves. "We've known all this time that oil is there, but BP has not been proactive in trying to remove it."
Mitchell Roffer, president of Roffer's Ocean Fishing Forecasting Service and an adjunct professor at the Florida Institute of Technology, shares Graves' concerns about the storm dredging up the old crude. "This is something that we talked about way back in May following the gulf spill," he said.
Roffer and others then argued against the widespread use of chemical dispersants to combat what would become the worst oil spill disaster in U.S. history.
"All it was doing was putting oil at the bottom of the ocean -- out of sight, out of mind," Roffer said. "I strongly believe that there is going to be some oil coming back up from submerged depths, into the water column and onto beaches."
But BP rejects such dire predictions. "Consistent with the past two hurricane seasons, we do not expect any significant impact of residual MC252 oil following Hurricane Isaac," BP spokesman Ray Melick told HuffPost in an email.
Still, should any oil surface, Melick said BP would be on top of it. "We have repeatedly demonstrated our ability to respond quickly following severe weather," said Melick. "We will do the same as necessary after Hurricane Isaac."
The idea that oil deep on the ocean floor could be stirred up by a tropical storm is debated, though a growing body of research does support the possibility.
"Winds will push water away from the center of a storm, which causes an upwelling as the ocean tries to adjust," said Nick Shay, professor of meteorology and physical oceanography at the University of Miami. "It brings whatever is near the bottom up higher in the water column and currents can then push it towards the coast."
His research team has found upwellings from prior tropical storms as deep as 1,500 feet. Crude oil settled at such dark, cold depths tends to break down slower than oil closer to the surface.
Robert Weisberg, a marine scientist at the University of South Florida, follows the work of Shay and others. He, too, sees "no reason not to believe" that Deepwater Horizon oil will resurface. "We will know pretty soon," he said. "Isaac will do his own talking."
Less controversial is the potential rise of oil buried in the sand or near the shore of Gulf beaches as the hurricane bears down on the coast.
"That's the most obvious way that the oil might come back into the public eye. Erosion could expose and churn up tar balls and tar mats," said John Amos, president of the nonprofit SkyTruth, where he is urging the public to post photos of oil pollution in the wake of Isaac.
Water surges could also flush water out of marshes -- where BP oil is known to have traveled -- and back into the coastal areas. Sea turtles, added Roffer, would be among the many that could suffer the consequences.
"This is the time of year that these little baby turtles hatch," he said. "Oil is not health food for anyone."