The lab, Boston Chemical Data Corp., said it found dispersant in a sample taken near Biloxi, Miss., almost a month after BP said it had stopped using the toxic chemical to break up the record amounts of crude spewed by the Gulf oil spill. The leak was finally capped on July 15.
The lab posted its data today on the website of the Louisiana Environmental Action Network in a move that could fuel the debate over the status of the cleanup in the Gulf of Mexico.
Parts of the gulf have been reopened to fishing and shrimping after the federal government declared the waters safe.
The lab's findings "again point to evidence that the 'all clear' is being sounded way too early," said Stuart Smith, attorney for both the fishermen's union and LEAN, which is suing BP on their behalf. "I do not believe a robust statistical sampling has occurred to prove that it's safe."
Water samples analyzed by Boston Chemical show oil and toxins in crab. But the key finding, according to Marco Kaltofen, the lab's president, is the presence of the Corexit dispersant used to break up the oil in coastal water near Horn Island, off Biloxi.
BP has said repeatedly the last day it used any dispersant was July 19. Environmental Protection Agency spokeswoman Alicia Johnson confirmed the agency believes that to be the case.
But Kaltofen said the time frame raises a question.
"Why on Aug. 9 did we find on a relatively concentrated pool of dispersant on the surface, well outside where the dispersant was going to be sprayed? It shouldn't have been there," Kaltofen told AOL News. He added that the high concentration in the sample suggested the dispersant was not carried inland from open water.
"What person or process got this dispersant with such a high concentration into inshore waters?" Kaltofen said.
Fishermen working the gulf say flatly they don't believe that BP actually stopped using the dispersant. But Kaltofen said he has talked to scientists who are searching for a more scientifically sound reason. One possibility: Could the dispersant have reconstituted itself on the surface?
"We just don't know enough about this yet," he said.
In all, Boston Chem has taken 250 samples from western Louisiana to the Florida Keys. The EPA has taken 300 water samples near shore, and found one "indication of a possible dispersant constituent near Louisiana," according to an e-mail from the agency.
"The location was sampled several other times with no other detection," the agency said, adding that it is continuing to monitor the region for "any possible safety and health threats."
[UPDATE, Sept. 3: The EPA now says it has analyzed 431 samples for DOSS, a component found in Corexit. Overall, the agency said it has taken more than 1,000 samples in near-shore waters.]
Between June 27 and July 20, the National Oceanic and Atmospheric Administration sampled 153 fish in the area reopened to fishing and is continuing to test samples of fish caught throughout the gulf. NOAA scientists have found no oil in the area reopened for fishing since early July, according to a report by the agency.
The Food and Drug Administration said in a statement that seafood samples from reopened fishing waters have passed sensory testing for contamination with oil and dispersant.
Scientific data gathered by the government "indicate that the dispersants used in the Deepwater Horizon response are unlikely to build up in the flesh of the fish," the FDA said. "This is primarily based on the assessment of their physical properties, which indicate that these compounds do not penetrate the gills or bodies of fish, and will not be concentrated in edible tissues of seafood."
The credibility of an analysis by a firm hired by attorneys suing BP will inevitably be challenged in court by the oil giant. Yet there is so much suspicion about the government's conclusion that much of the oil had disappeared that any report justifying those fears carries added weight.
Anecdotally, fishermen recount episodes where fishermen and cleanup crews have worked the same waters.
"My cousin was working in Grand Isle. He told me they had people who were shrimping alongside people who were skimming oil," said Louis Molero, a Louisiana oysterman.
"Everybody believes the government is sugar-coating this," he said. "If we get one person sick due to oil, our business is really going to be in a mess."