There are "large gaps" in data now being gathered on the health of the 34,000 workers cleaning up the largest oil spill in U.S. history and growing concern that BP Plc will fail to publicize problems if they arise.

Linda McCauley, dean of the Emory University's school of nursing in Atlanta, said, "It's kind of scary" that the cleanup workers are hired by "the people who are actually at fault" and not the local government, "where we know there can be transparency." She led a panel on health effects of the Gulf spill at a U.S. Institute of Medicine hearing today.

Eight panel members interviewed before the meeting said the U.S. government needs to fund years of monitoring of cleanup workers to adequately assess exposure risks to toxic chemicals as a result of the Gulf of Mexico spill. Several likened the lack of coordination in monitoring to the Sept. 11, 2001, World Trade Center attack when the government failed to foresee health fallout that left thousands with long-term illnesses.

The Institute of Medicine, a nonprofit body based in Washington, convened the workshop at the behest of Health and Human Services Secretary Kathleen Sebelius. Volunteer members of the IOM, part of the United States National Academies, have been asked to supply guidance on what types of programs her agency should consider funding.

Deadly Explosion

The oil spill was caused by an April 20 explosion aboard the Deepwater Horizon rig, which London-based BP leases from Switzerland's Transocean Ltd. The blast killed 11, and the wellhead may be leaking as much as 60,000 barrels a day, according to a government-sponsored panel.

Children are among the most-vulnerable population after the spill workers, said Irwin Redlener, a member of the National Commission on Children and Disasters and director of Columbia University's National Center for Disaster Preparedness.

"This is Round 2 for these children," Redlener told the workshop. These are children who are recovering from the damage caused by 2005's Hurricane Katrina and now face the oil spill, he said.

Redlener said children are more susceptible to inhalation problems associated with a spill, absorption through the skin and ingestion, given that many put things in their mouths and fail to follow public health guidelines. Children in the region are suffering psychologically, emotionally and academically from the combined effects of Katrina and the spill, he said.

More Vulnerable

Scientists also are seeing "large gaps in the data" on the health impact of the spill, said Paul Lioy, vice chairman of the Department of Environmental and Occupational Medicine at UMDNJ-Robert Wood Johnson Medical School in Piscataway, New Jersey.

Lioy spoke at the panel today on routes of exposure and at- risk populations. In an earlier phone interview, he said the data haven't shown "large exposures, but I don't know where it was taken, or if it was in the places of most-significant concern."

None of the eight researchers interviewed set a cost for large-scale federal monitoring of worker health. The government must track the extent of exposure, gather consistent and clear data, and routinely test cleanup workers to detect early signs of problems, the researchers said in interviews over the past several days.

NIH's $10 Million

National Institutes of Health Director Francis Collins said $10 million had been set aside to study the public health impact of the oil spill, focusing on cleanup workers and coastal residents.

While there are relatively few studies on the long-term ramifications of exposure to crude oil toxins, the workshop heard a report from Blanca Laffon, a toxicologist at the Universidad de A Coruna in Spain, on research on cleanup workers at the 2002 Prestige Oil spill off the Galician Coast.

The research found biomarkers that indicate these workers, coastal residents and fishermen faced a higher risk of cancer than the rest of the population, Laffon said in an e-mail before her panel appearance.

"We analyzed some genotoxicity biomarkers that are early indicators of an increase in the risk of cancer and observed that their values were higher than those in the non-exposed control population," said Laffon. "This does not mean that these people are going to develop cancer in several years, but that their risk is increased."

Not Well Coordinated

Even with the formation of registries for such groups as spill workers, which are a post-9/11 innovation, activities are not yet well coordinated and information is incomplete, Lioy said.

"Oil is a complex mixture containing substances like benzene, heavy metals, arsenic, and polynuclear aromatic hydrocarbons -- all known to cause human health problems such as cancer, birth defects or miscarriages," said Kenneth Olden, founding dean of New York's CUNY School of Public Health at Hunter College, who is monitoring a panel on possible delayed effects. "The potential here is huge and we have to be diligent about protecting the public health and these workers."

For the public at large, the threat is less clear because of the uncertainty about the degree of exposure, Lioy said in a telephone interview.

"I don't think the levels are high enough for concern," he said. "But this is an ongoing event. Every day is Day One. Every place can be Ground Zero."

The Centers for Disease Control and Prevention, working with the U.S. Environmental Protection Agency, has issued health warnings to certain groups.

Unborn Babies

"Although the oil may contain some chemicals that could cause harm to an unborn baby under some conditions, the CDC has reviewed sampling data from the EPA and feels that the levels of these chemicals are well below the level that could generally cause harm to pregnant women or their unborn babies," the CDC said on its website.

While they suggest there is no threat, the CDC simultaneously advised "everyone, including pregnant women" to avoid spill-affected areas.

The Atlanta-based CDC also has alerted spill workers to the potential of heat stress from working in temperatures more than 90 degrees Fahrenheit and sometimes above 100. Among the workshop participants' first priorities is to make sure workers are given adequate protective gear, something that didn't happen for first responders to the World Trade Center attack, said Hunter College's Olden.

Gloves, Respirators

"These workers don't need only rubber gloves and boots, they may need respirators to protect against inhalation of some pretty toxic fumes," said Olden, who is also a former director of the National Institute of Environmental Health Sciences. "The one thing I keep hearing is that many workers were not and are not wearing protective gear. That concerns me."

Some oil spill workers have experienced nausea, headaches and other symptoms associated with exposure to toxins, Emory University's McCauley said.

There is also the threat of mental disorders and stress- related health problems, said David Abramson, director of research for Columbia's National Center for Disaster Preparedness in New York and a panel speaker.

"We're seeing indications that people are drinking more," said Howard Osofsky, a psychiatrist from Louisiana State University in Baton Rouge.

Risks Downplayed

While some 9/11 first responders exhibited post-traumatic stress disorders, Abramson said the curve for this disease related to the spill won't look the same because the Gulf disaster isn't an event with an end. "This is an event that keeps unfolding," he said. "There is a loss of culture that the entire region will feel."

Shira Kramer, an epidemiologist who has conducted research for the petroleum industry on the health consequences of exposure to petroleum, said she is concerned that the risks are being downplayed.

"It's completely scientifically dishonest to pooh-pooh the potential here when you are talking about some of the most toxic chemicals that we know," said Kramer, who is founder and president of consulting firm Epidemiology International in Hunt Valley, Maryland. She isn't involved with the Institute panels.

"When you talk about community exposure, you are talking about exposures in unpredictable ways and to subpopulations that may be more highly susceptible than others, such as those of reproductive age, people who are immuno-compromised, children or fetuses.

'With the World Trade Center, there have been unpredictable adverse health effects to the populations that were exposed and not just the workers," she said. "In this case, we have a soup of chemicals from the crude, chemicals from the dispersants and pollutants that were already in the water. Who can say how they will interact?"