Workers struggling in the heat to clean up oil from the ruptured BP well in the Gulf of Mexico risk short-term lung, liver, and kidney damage from fumes, experts said.
Studies of the health effects after seven supertanker spills showed that clean-up crews had suffered short-term health problems from volatile organic compounds emitted by the oil, the experts told an Institute of Medicine hearing in New Orleans, US.
Protective gear helps, but the workers usually take it off in the summer heat of the Gulf, they said.
"You really are talking about a triangle of heat, chemical exposure, and then the behaviour changes that you see as a result," said Linda McCauley, dean of Emory University's School of Nursing in Atlanta, US.
Heat stroke a big concern
"Exertional heat stroke is our critical concern," added Thomas Bernard of the University of South Florida, US.
The April 20 spill is the worst in US history and oil is still pouring into the Gulf. Workers in boats are trying to skim, siphon and soak up the oil, and are deploying booms to try to delay its drift to shore.
Fisheries in contaminated areas have been closed and oil is washing up onto beaches and into fragile marshes.
Earlier on Tuesday a US federal judge overturned the Obama administration's six-month ban on deep water drilling, granting a request by more than a dozen oil services companies.
Various government departments are keeping eye on the health of workers and seafood is being inspected for potential contamination.
Irritating but not deadly
Health and Human Services Department officials told a Congressional hearing that little is known about the health impacts on people of oil spills.
The oil itself is irritating but not especially dangerous to touch or even swallow, Dr John Howard of the Centres for Disease Control and Prevention told a hearing of the Senate Committee on Health, Education, Labour and Pensions last week.
"Swallowing small amounts (less than a coffee cup) of oil will cause upset stomach, vomiting, and diarrhoea, but is unlikely to have long-lasting health effects," he said.
But experts told the Institute of Medicine, an independent body that advises the federal government on health issues, that there can be short-term effects from fresh oil fumes.
400 tanker spills since 1960s
"At least 400 tanker spills have occurred since the 1960s, and 38 of them were supertankers, and only seven of those have been studied to date," said Nalini Sathiakuma of the University of Alabama at Birmingham.
These studies have shown consistently that the eyes, skin and nervous system can be affected from exposure to the organic compounds in the oil and the fumes, Sathiakuma said. "Personal protection equipment definitely reduces exposures, and education particularly of cleanup workers is extremely important," she said.
"Short-term lung, kidney, and liver functions could be affected."
The good news is that the oil breaks down in the water, becoming gummier but less toxic, said Edward Overton, professor emeritus of environmental science at Louisiana State University.
"Thirty to fifty percent of the oil is gone in the first week," he said, noting that bacteria degrade the more toxic components as the oil becomes weathered. - (Emma Ashburn/Reuters Health, June 2010)