Whatever the environmental costs of the Gulf of Mexico oil spill, the impact on human health seems to be relatively small, at least till now.
With more than 33,000 workers and volunteers deployed to the spill, there have been 143 reports of oil-related illnesses logged by the Louisiana Department of Health and Hospitals as of this week. That includes 108 spill workers and 35 members of the public. Twenty people — 17 workers and three community members — were briefly hospitalized for complaints usually related to strong oil odors. Everybody felt better once they left the smelly area though, said Lisa Faust, a spokeswoman for the health department.
But workers struggling in the heat to clean up oil from the ruptured BP well run the risk short-term lung, liver, and kidney damage from fumes, some experts said on Tuesday.
They had gathered at the request of the U.S. Department of Health and Human Services to assess the potential health risks of the Gulf of Mexico oil spill and find ways to minimize them.
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 behavior changes that you see as a result," said Linda McCauley, dean of Emory University's School of Nursing in Atlanta.
"Exertional heat stroke is our critical concern," added Thomas Bernard of the University of South Florida.
So far, 357 oil exposure complaints have been reported to the American Association of Poison Control Centers.
But health officials say that reports of headaches, nausea, sore throat and dizziness may only be the immediate short-term effects of the spill. To track potentially serious and long-term effects, such as the development of cancer or other illnesses, the National Institute for Occupational Safety and Health has launched "the most robust monitoring system" of oil spill workers to date. As of last week, 14,664 workers had volunteered to be part of a long-term tracking system.
The oil itself is irritating but not especially dangerous to touch or even swallow, Dr. John Howard of the Centers for Disease Control and Prevention told a hearing of the Senate Committee on Health, Education, Labor and Pensions last week.
"Swallowing small amounts (less than a coffee cup) of oil will cause upset stomach, vomiting, and diarrhea, 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.
"Petroleum has inherent hazards and I would say the people at greatest risk are the ones actively working in the region right now," said Dr. Jeff Kalina, associate medical director of the emergency department at The Methodist Hospital in Houston. "If petroleum gets into the lungs it can cause quite a bit of damage to the lungs [including] pneumonitis, or inflammation of the lungs."
"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 us consistent evidence for ocular, neurological, dermal exposure as a result of exposure to volatile organic compounds. 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."
"Volunteers will be at the highest risk," one panel member, Paul Lioy of the University of Medicine & Dentistry of New Jersey and Rutgers University, stated at the conference. He was referring largely to the 17,000 U.S. National Guard members who are being deployed to help with the clean-up effort.
Many lack extensive training in the types of hazards -- chemical and otherwise -- that they'll be facing, he said. That might even include the poisonous snakes that inhabit coastal swamps, Lioy noted.
Many National Guard members are "not professionally trained. They may be lawyers, accountants, your next-door neighbor," he pointed out.
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.
The experts added ergonomic hazards, high noise levels, heat stress and everyday physical injuries to the list.
Going forward, many other risks will fall into the category of "unknown."
"Some of the risks are quite apparent and some we don't know about yet," said Kalina. "We don't know what's going to happen six months or a year from now."
To illustrate, he hearkened back to another national disaster. "None of us imagined as we watched folks go to Manhattan to clean up after 9/11 that they would be coming down with diseases due to the dust and particles that were in the air," Kalina said.
The slick has already closed fishing grounds, killed hundreds of turtles and seabirds and dozens of dolphins and affected the coastlines of four US states.
Emergency workers and fishermen in Florida said the oil was now being washed ashore on Pensacola Beach.
"It's just a line of black all the way down the beach as far as you can see in both directions. It's ruined," said Pensacola fisherman Steve Anderson.
Meanwhile BP says it has reinstalled a containment cap on its blown-out well in the Gulf of Mexico after an accident unleashed a torrent of oil.
BP was forced to remove the cap after an underwater robot bumped into the venting system.
Gas had risen through the vent that carried warm water down to prevent ice-like crystals from forming in the cap.
The cap has been partially containing the leaking oil and directing some of it to a surface ship.
The decision to remove the cap for repairs meant that oil was flowing unhindered into the ocean for about 10 hours on Wednesday.
Crude has been leaking at a rate of between 30,000 to 60,000 barrels per day, according to US scientists. The cap has been collecting roughly 16,000 barrels every 24 hours, BP says.
In a separate development, two workers involved in the clean-up operation died, Coast Guard Adm Thad Allen said.
One death, he said, appeared to have been a swimming pool-related accident, while the second one was an apparent suicide.
It was not immediately known when the deaths had occurred and which company either of the two victims had been working for.
In another development the Justice Department is seeking to delay a court ruling that overturned the moratorium imposed by the Obama administration on new drilling in the Gulf.
The Justice Department says a delay would serve the public interest by eliminating the risk of another drilling accident like the one that caused the Gulf of Mexico oil spill while new safety equipment standards and procedures are considered.
The Interior Department imposed the drilling moratorium last month in the wake of the BP disaster, halting approval of any new permits for deepwater projects and suspending drilling on 33 exploratory wells.
On Tuesday, Feldman overturned it, saying the government simply assumed that because one deepwater rig exploded, the others pose an imminent danger, too.
Interior Secretary Ken Salazar's determination that a threat exists has firm support from a variety of sources, the Justice Department argued in court papers filed with the U.S. District Court in New Orleans seeking the delay. It is also appealing Feldman's decision.