HAMPTON ROADS, VA.   December 15, 2004

How Good is Good Enough?

CHAPTER 5: THE BEST TEST

The world's most accurate test for depleted uranium exposure is now available - but only in Britain and Germany. The Pentagon says U.S. vets don't need it.
 

 Photo Gallery
Exploring the dangers of depleted uranium.
Exploring the dangers of depleted uranium.

 CHAPTER 5 IN BRIEF

Depleted uranium bigger issue in U.K.
Public concern about health hazards from depleted uranium weapons is higher in Britain than in America. Pressure from thousands of sick British vets and anti-nuclear activists prompted the British government to finance research that led to the most accurate and precise urine testing available for depleted uranium.

Key to the testing: Mass spectrometer
Mass spectrometers are used to identify unknown materials, especially in small quantities. This mass spectrometer used by the U.S. military for examining urine samples is less capable than the ones being used by the British.

A Pentagon health expert
Lt. Col. Mark Melanson says that he's not familiar with the British testing pro­gram but that the U.S. version is more than adequate to detect quan­tities of de­pleted uranium that endanger health. British testing officials say they've had no inquiries about their methods or procedures from the U.S. government, despite a promise by Gen. Richard Myers, chairman of the Joint Chiefs of Staff, to look into these programs and compare them with proce­dures used by the U.S. military.

Internal radiation expert Beate Ritz
Pentagon officials say their reliance on a less-than-the-best test is OK because of all the research done with uranium miners, millers and pro­cessors that shows how much ura­nium dust can be inhaled safely. They point to a U.S. Institite of Medince report for support. But Beate Ritz, a cancer researcher the institute turned to for expertise on internal radiation, says there's too little known about depleted uranium exposure to reach the conclusions the military has.

Changes in blood DNA indicate possible cancer
Examinations of troops with depleted uranium shrapnel, and studies with rats who inhaled the metal, show a link between internal depleted uranium and changes in the DNA of genes in the blood, says Richard J. Albertini, a cancer researcher in Vermont. He and other scientists believe those changes in DNA indicate cancer in humans.

After weighing risks, she'd choose weapons
Terry Pellmar, a researcher at the Armed Forces Radiobiological Research Institute, has conducted important research on depleted uranium's impact on animals. She says that while some increased risks might come from the weapons' use, she would feel safe trusting the Pentagon's assessment of dangers.

 VIDEO

Watch a training video about depleted uranium.

 ABOUT DU

What is it?
It's a byproduct of making "enriched uranium" for nuclear weapons and fuel. "Enriched uranium" is somewhat misleading because processors take uranium with natural levels of radioactive isotopes, primarily Uranium 238 and Uranium 235, and remove as much of the U-235 as possible. Weapons makers and nuclear plant owners want almost-pure, highly radioactive U-235. What's left behind is primarily U-238 (other isotopes remain, in very small quantities). That substance has about 40 percent less radioactivity than natural uranium and is "depleted uranium."

What makes it so important?
It's proven to be the most effective tank-killing weapon ever. A round of depleted uranium no bigger than your little finger can stop a top-of-the line tank without depleted uranium armor. The weapons get sharper as they hit and plow through thick steel. They also create fireballs of thousands of degrees, a potent combination.

What is the controversy?
As they strike, the weapons get sharper by peeling off millions of shards of burning depleted uranium. Those burning pieces become microscopic dust that can be inhaled. Depleted uranium is a mildly radioactive, toxic substance that can cause damage to live tissue and cells once inside the body.

 THE SERIES

Part One: Looking for a cause, looking for a cure

Part Two: From the nose to the brain

Part Three: The silver bullet

Part Four: The battlefield at home
 
BY BOB EVANS
247-4758

December 15, 2004

In Great Britain, veterans of the 1991 Gulf War are signing up to take the world's most precise test for determining exposure to depleted uranium.

The U.S. government advertises a test for its veterans of that war too. But the test that it offers can't detect uranium in low amounts, has a high error rate and uses equipment that's less sensitive and accurate than the machines the British are using. U.S. vets and soldiers who've had this test say they've been told they weren't exposed when, in fact, the tests were simply incapable of detecting whether depleted uranium was present.

Members of Congress have asked the Pentagon to look into testing programs in other countries. The chairman of the Joint Chiefs of Staff promised to do that in April. But after that promise was made, the officer in charge of U.S. testing said he had no reason to gather such data because his test was good enough.

"Our labs would easily detect depleted uranium levels approaching U.S. peacetime safety standards," says Lt. Col. Mark Melanson, who runs the health physics program at the Army Center for Health Promotion and Preventive Medicine.

One of those labs handles all depleted uranium testing for the Department of Veterans Affairs.

Randall Parrish, a scientist who played a big role in developing the British test, says he can't understand why the United States is satisfied with an inferior test.

"It is incorrect to assume that a low concentration of uranium in urine means there is no contamination," he says, because there's no good data to support that conclusion.

The U.S. government's refusal to adopt a state-of-the art test also prevents researchers from finding out why tens of thousands of veterans of the Gulf War have debilitating illnesses, says Mohamad B. Abou-Donia, a researcher at Duke University.

Abou-Donia has conducted many significant experiments into the causes of illnesses suffered by Gulf War vets. He also recently published a study that reviewed available scientific work on the health effects of depleted uranium.

Knowing which veterans were definitely exposed to depleted uranium - not just those who might have been exposed to huge doses - would fill a huge gap in the research, he says.

But until a better test is adopted and used on a larger number of vets, that data isn't available, he says.

So there's no certainty about who was exposed and who was not. Until scientists can reliably determine who was exposed and who was not, they can't prove or disprove links between depleted uranium and individual veterans' health problems, Abou-Donia says.

Veterans and scientists have questioned for several years whether the use of depleted uranium weapons in the Gulf War is one of the reasons that so many veterans of that war came home weak and full of pain.

The weapons provided a decisive edge in tank warfare in the 1991 and 2003 battles in the Persian Gulf region. They also left behind millions and millions of pieces of easily inhalable black dust that's toxic and mildly radioactive. The dust is a necessary result of using the weapons to hit and destroy hard targets.

In recent years, researchers have shown that laboratory animals that inhaled depleted uranium dust developed cancerous tumors. They've also found that a single particle of depleted uranium can alter the genetic structure of nearby cells in ways consistent with widely held scientific beliefs about the way cancer starts in the human body. And they've found evidence that once depleted uranium gets in the body, it migrates through the bloodstream to the brain, testicles, lungs, kidneys and bones, where it can reside for years.

But all that research constitutes preliminary steps toward figuring out how big a problem the dust from depleted uranium weapons might be, researchers say. Meanwhile, the military plans to significantly reduce its investigations into possible health effects resulting from depleted uranium, as well as other possible causes of Gulf War-related illnesses.

IN BRITAIN, SAME COMPLAINTS PROMPTED DIFFERENT RESPONSE

The government's attitude toward critics of the weapon isn't much different in Britain. British and U.S. troops are among the few who actually used depleted uranium weapons in battles. A large number of British vets have also been complaining about health problems similar to those experienced by U.S. armed forces from that war.

Parrish says his government paid to develop the more accurate tests for veterans in part because of political pressure and in part because of medical experts' suspicions that existing tests yielded inconclusive and inadequate evidence of exposure.

Those tests were being used to dismiss the veterans' benefits claims. Some British veterans went to independent labs and received results that proved depleted uranium was in their urine. Analysis of 24 hours' worth of urine is the commonly accepted method of determining whether someone has been exposed to uranium of any kind.

The British veterans' pleas for a better depleted uranium test also got support from the British Royal Society, an invitation-only group of prominent scientists. The Royal Society carries clout in Britain: It dates to 1660, and its members are readily acknowledged as among the best scientific minds in the country. Society members decided to tackle the problem of Gulf War illnesses independent of the government, and after several years, they issued a series of findings.

While those findings didn't contradict the government's official viewpoint in many ways, the society did call for a testing program that could more accurately detect whether someone had depleted uranium in their body. That, coupled with activism by veterans groups, left the government little political choice.

It took about two years to develop the highly accurate tests, says Parrish, a professor of isotope geology at the University of Leicester.

In addition to his teaching, he runs a laboratory at the British Geological Survey supported by Britain's Natural Environment Research Council. The council is independent of the government and is similar to the National Science Foundation in the United States, Parrish says.

Parrish and David Coggon, a scientist and chairman of the board that runs the testing program, say there are only four labs (three in England, the other in Germany) that have adopted the more rigorous testing regimen so far.

Part of the difficulty of testing for depleted uranium in someone's body is that you can't cut up a person and look for the uranium like you would if it were in a rock, soil sample or lab rat. That's why scientists look for it in urine. While not a perfect source, it's the best available right now, Parrish and others say. Even the U.S. military agrees.

Finding depleted uranium in the body gets complicated. Natural uranium is in everyone's body because it's in the food and water we ingest. Therefore, there's natural uranium in everyone's urine. It's difficult to accurately identify the depleted uranium as opposed to the natural uranium, in part because the amounts of both are so small.

Once obtained, the uranium in a 24-hour urine sample is typically measured in nanograms. A nanogram is one-billionth of a gram or one billion times lighter than a dollar bill. If a total of 1 nanogram of natural and depleted uranium are involved, the quantities of each are even lower. It takes extremely sophisticated machines to help find and identify the microscopic bits of depleted uranium.

The British and U.S. governments have been giving veterans and soldiers urine tests for depleted uranium for years. But unless the soldiers had relatively large quantities of uranium in their bodies, the tests couldn't detect depleted uranium apart from natural uranium without a high margin of error, Parrish and other scientists say.

LIMITATIONS ON TESTS CREATE QUESTIONABLE RESULTS

U.S. military testing officials say that unless a sample has a relatively high total uranium level, no attempt is made to determine how much uranium is natural and how much is depleted uranium. The level is deemed safe, and there's no need to tell the difference, they say.

As a result, U.S. and British veterans have been told for years that they tested negative for depleted uranium, Parrish and others say. Instead, all that had been demonstrated was that the methods used in testing were incapable of detecting depleted uranium in such small quantities.

Painstakingly careful methods to collect the urine and separate the uranium from the liquid and other chemicals in the sample are important, Parrish says.

Axel Gerdes, a German scientist who worked with Parrish to develop the tests, says a crucial difference involves the methods used to concentrate the uranium in urine before it's analyzed.

He says the labs used by the U.S. Army dilute the urine with water, which makes it easier to examine, and take other shortcuts that reduce the time and manpower to do the tests. That comes at the cost of losing the ability to detect small quantities with accuracy, he says, by a factor of about 1,000.

SUPERIOR SPECTROMETER USED BY BRITISH LABORATORIES

The British testing program also calls for using superior hardware to aid the analysis, Gerdes and Parrish say.

Several machines are employed for that task, they say, including a multicollector ICP mass spectrometer. A mass spectrometer is a machine used to determine the contents of an unknown substance. A multicollector ICP mass spectrometer is an even more sophisticated version that's specially equipped to accurately measure minute quantities of radioactive substances, including the various forms of an element known as isotopes. The way that scientists tell the difference between natural uranium and depleted uranium in a sample is by counting these isotopes, a process that at times involves tiny amounts of an element.

Scientists using the procedures and hardware developed for the British test are now able to reliably identify the difference between depleted uranium and regular uranium in samples with as little as 0.1 nanogram of total uranium per liter of urine, Parrish says. That's 10 billion times lighter than a dollar bill. All this is done with a margin of error of less than 1 percent, making it a very accurate test.

Lt. Col. Melanson, who oversees much of the Pentagon's scientific research into the health hazards of depleted uranium, says the most exacting lab test used on U.S. veterans and active-duty military personnel must have at least 3 nanograms of total uranium to examine per liter of urine. That's 30 times more than the minimum for the new British test.

The most sophisticated U.S. testing labs use a quadruple ICP mass spectrometer, Melanson says. Parrish and other experts in using mass spectrometry to identify materials say that's a much less capable machine than the multicollector type that the British are using, a machine that's been available for about 10 years.

Gerdes now works at a university in Germany and does testing there for privately financed groups. He has an even more sensitive version of the machine than the British labs do. He says it enables his lab to accurately detect even smaller quantities of depleted uranium.

Earlier this year, nine soldiers from a New York-based National Guard unit who had health problems after serving in Operation Iraqi Freedom had their urine tested at Gerdes' lab at the University of Frankfurt.

Gerdes says the nine veterans had anywhere from 1.6 to 5.7 nanograms per liter of uranium in their urine. Of those, five had little or no depleted uranium in their samples, while the others' samples contained 1.2 percent to 8.2 percent depleted uranium.

After publicity about the tests in the New York Daily News, those veterans were tested by the labs used by the U.S. military, says Michael J. Kilpatrick, deputy director for the Pentagon's office of health protection for deployed troops. None had enough total uranium in their urine to be concerned about, Kilpatrick says, and the U.S. labs didn't find any depleted uranium. The cause of the soldiers' illnesses remain undiagnosed.

Gerdes says the use of total uranium as a guide to the level of depleted uranium in someone's body is a mistake because there's often no correlation between how much total uranium is in a sample and what percentage of it was depleted uranium. That's an important point that the U.S. military seems to overlook, he says. The U.S. military says the only difference is that depleted uranium is less radioactive and therefore less harmful.

After initial reports about the results from Gerdes' lab involving the New York veterans, several members of Congress questioned whether the U.S. military should be looking at more rigorous testing. They directed the questions to Gen. Richard Myers, chairman of the Joint Chiefs of Staff, in a congressional hearing April 20.

They specifically asked about tests being developed in other countries, in light of the different results involving the New York National Guard unit.

JOINT CHIEFS CHAIRMAN SAID STAFF WOULD LOOK INTO TESTS

Myers told them he didn't know about the other countries' testing but that he would look into the matter.

Coggon, head of the board that oversees the British testing, says he's not aware of any effort from the United States to get information about the processes or procedures developed there. Melanson, the U.S. military official deemed the most knowledgeable about depleted uranium testing, says he's not familiar with the British program and sees no need to inquire.

The tests available in the United States are good enough, he says, and are capable of determining the presence of depleted uranium at levels nearly 1,000 times lower than the health safety standards established in the United States.

When U.S. troops or veterans are tested, they're usually told that their results didn't contain uranium outside the normal background levels of uranium intake and therefore aren't considered a health risk.

That standard is set by the U.S. Nuclear Regulatory Commission and is based on a representative sample of 1,006 people given urine tests collected and analyzed by another federal agency. But the NRC attaches a warning to those standards, noting it's "unknown" whether the levels of uranium in the survey "represent cause for health concern." It's merely a level of uranium in urine for a cross section of the population 6 years and older and says nothing of how healthy or unhealthy they are or will be, the NRC says.

The NRC further cautions that "more research is needed" to determine what the healthy level is.

In the draft of a 2002 report outlining the issues involved in using urine testing for soldiers' exposure to depleted uranium, Melanson's own staff pointed out those same limitations and warnings.

One thing everyone agrees on is that no one has been able to credibly determine how much depleted uranium is in someone based on the level of depleted uranium in their urine.

Research shows pretty clearly that when any uranium is swallowed, it passes through the intestines and is excreted quickly. Particles created by the use of depleted uranium weapons, when inhaled, stay in the body much longer, Pentagon research shows.

The tiny bits of depleted uranium created when the weapons hit hard targets tend to be what chemists call ceramic, which means they don't easily break down in liquid. Various forms of uranium have a wide range of solubility, Parrish says. The effect of the high heat from the explosions and other factors make this particular kind of uranium a big unknown regarding how much and how fast it breaks down in the body and enters the blood and urine.

DUST IN LUNGS DOESN'T DISSOLVE QUICKLY, STUDY FINDS

The Army's recently completed five-year $6 million Capstone study of those tiny pieces of depleted uranium concluded that there's "a significant source of uncertainty" regarding how fast inhaled particles would dissolve in simulated lung fluid. Still, the study concluded, there was no significant health risk from inhaling particles of depleted uranium that result from use of the weapons in combat.

The Capstone study said the vast majority of the particles created from use of the weapons and small enough to be inhaled took 100 days or more before dissolving halfway in simulated lung fluid. Generalizations were not easy, it said, but the smallest particles tended to be the least soluble. That means that pieces more likely to get more deeply into the lungs last longer.

Anywhere from less than 1 percent to 35 percent of the inhalable-sized pieces tested in Capstone dissolved halfway in 10 days or less, the study found, while 58 percent to 99 percent took more than 100 days to dissolve half their mass. Dissolution of half of the mass of a contaminant is the government's standard measure of how long it might take to clear something from the lungs after occupational exposures.

That data indicates that even the smallest particles could stay in the lungs for several years, Melanson says, though he doubts that they would pose any significant health risk.

So far, the British have tested only about 30 troops as part of making sure that their procedures are accurate. None of those people had depleted uranium in their samples.

Parrish says it's possible that by now, all the inhaled depleted uranium that will ever dissolve in these soldiers' lungs has dissolved and the rest will remain inside without a way to detect it. He also says it's possible that all the uranium is dissolved.

That's one reason why the testing program is so important, he says - to find out, instead of speculating.

U.S. government scientists still find evidence of depleted uranium in the urine of troops with shrapnel wounds. But those larger particles tend to be more soluble than the dust that's inhaled, the Capstone study says.

Some researchers say the relatively lower solubility of depleted uranium dust could spell even more trouble for the veterans than thought. If those little pieces in the lungs and nearby lymph nodes aren't dissolving quickly and getting flushed out of the body through the blood and urinary tract, then they're sitting next to live tissue and blood cells, emitting DNA-altering alpha particles for years.

Under this theory, it would be extremely important to know how much of the uranium in someone's body is natural uranium, as opposed to depleted uranium, even if there are small quantities involved. That's because the level of natural uranium in someone's body is mostly swallowed, and more than 90 percent of it is flushed from the body within a day or two through excretory systems. The swallowed uranium therefore doesn't stay in one place to irradiate tissue or blood for hundreds of days.

Richard J. Albertini, a cancer researcher at the University of Vermont, says those pieces of radioactive dust in the lungs, as opposed to the digestive system, are important for another reason.

LOCATION OF THE METAL MAKES A BIG DIFFERENCE

Research indicates that inhaled depleted uranium can cause genetic mutations in blood, he says. Those mutations signal what very well might be the first step toward cancer. Because all of a person's blood passes through the lungs to pick up oxygen to be distributed throughout the body, large quantities of blood are subject to mutations from exposure to depleted uranium. In contrast, he says, veterans with shrapnel in isolated parts of the body aren't irradiating as much of their blood because their wounds are rarely in places where most blood circulates.

Kilpatrick dismisses these arguments, in part because natural uranium is even more radioactive than depleted uranium. He also dismisses a possible link between inhaling depleted uranium and the neurological problems that seem to form the bulk of complaints by Gulf War veterans.

None of the neurological problems associated with those vets has been noted in the 50 years of research involving workers in the uranium industry, he says. So if the quantities of either form of uranium are lower than the Pentagon testing program shows, there shouldn't be a problem, he says.

The British Royal Society's final report on the hazards of depleted uranium basically agreed with the Pentagon's views of the health risks. But it called for better testing to help scientists get a better understanding of the relationship between intake and risks, as well as help figure out what might be ailing individual veterans.

Abou-Donia, the Duke University scientist who recently published a survey of available research on depleted uranium, says data from better tests - such as the ones being done in Britain - could prove very helpful. "Absolutely. Any monitoring of this chemical would be helpful," he says.

Abou-Donia has been conducting experiments and other studies on various possible causes of Gulf War veterans' illnesses for several years. One of the biggest problems that scientists have in that field is a lack of fundamental data, he says.

If thousands of veterans in the United States got the new tests, the lack of data regarding depleted uranium might be eased, he says.

Scientists might be able to tell, for example, whether veterans who definitely have depleted uranium inside them also have a type of brain abnormality thought to be characteristic of the neurological symptoms among Gulf War veterans, he says.

But until now, no one has had a test considered reliable enough to detect small enough quantities to determine who was probably exposed and who wasn't.

Scientists don't know what causes the brain abnormalities in those vets, Abou-Donia says. But unlike other chemicals and causes under suspicion, the depleted uranium in urine is measurable and might still be in the body.

The level of exposure to chemical weapons, bug spray and other suggested causes of the veterans' illnesses isn't detectable at this late date because those toxins are long gone from the body and no one kept accurate records of doses and other information on the 1991 battlefield, Abou-Donia says. Those toxins have done their damage and are gone. That's one reason that finding the cause of the veterans' complaints has been so difficult.

ACTUAL BENEFITS OF NEW TESTS NOT DETERMINED YET

Gerdes, an environmental geochemist, says he questions whether there's a link between depleted uranium exposure and the illnesses suffered by veterans. But doing the science and the testing is an important step toward understanding the problem. "There is simply a need to do further research in this topic," he says.

Parrish says he's not sure what the testing is going to find. He notes that though the British government agreed to finance use of the new tests for veterans of the Persian Gulf War and peacekeeping missions in Bosnia and Kosovo, veterans of the continuing war in Iraq are tested with the less precise measurement.

A British Ministry of Defense spokesman says the new testing is considered important for veterans of the other wars because of the long period that's elapsed since the exposure and therefore the need to identify what might be smaller quantities.

He says the military is satisfied with the less-exact testing for veterans of the current fighting in Iraq and Afghanistan, though some will be given the more sophisticated tests as an expedience.

The new testing program for the British veterans is just starting. Advertisements and notices directed at veterans started in late September, and about 300 people have signed up so far, Coggon says. About 1,500 are expected to sign up, says Charles Williams, a spokesman for the Ministry of Defense.

Williams and Parrish say it will probably take six months to a year before enough tests are concluded to get an accurate picture of how many vets have been exposed and at what level.

Parrish says that as long as Britain and the United States refuse to let outside independent laboratories handle the testing, there will be suspicions that the truth about exposures and possible problems are being concealed.

The two labs in Britain performing the tests are considered independent.

He says he and other lab workers do the testing and analysis, but they don't know whether they're working on "dummy" samples or actual veterans' urine. That's one of the many levels of exactitude they've built into the process to help ensure accuracy. Some dummy samples might be "spiked" with known quantities of uranium and depleted uranium in another lab and sent out with the vets' samples, but others are taken from people known to have no depleted uranium in their urine. That keeps the labs on their toes, Parrish says.

In the United States, the most precise testing that the Pentagon does is handled at a national Centers for Disease Control and Prevention laboratory, Melanson says.

When that federal agency does testing for the military, it won't release any information about the tests conducted there and won't even answer questions about the procedures, error rates or scientific standards for the tests, says Kathy Harben of the disease control agency.

She referred all questions about the agency's testing for the military to the Pentagon.

VETS SAY U.S. DOESN'T WANT TO PAY FOR BETTER TESTING

Steve Robinson, executive director of the Gulf War Resource Center Inc., a veterans rights group, says he suspects there are two reasons that the United States uses the less sophisticated testing method.

First, he says, is the cost.

Pentagon officials say their tests cost $200 to $400 a sample, depending on whether there's enough total uranium in the urine sample for the government to attempt to determine whether it contains depleted uranium.

Melanson initially refused to divulge the cost of this testing, saying it wasn't a factor in his decision-making.

Parrish says his test costs about $1,000 each.

Robinson and other veterans advocates say the second reason that the U.S. government doesn't want to use the more sophisticated tests is they're afraid the tests might help show possible links between the highly valued depleted uranium weapons and veterans' health problems.

"These are very effective weapons, and they want to keep them," says Steve Smithson, assistant director of the American Legion's Veterans Affairs and Rehabilitation Division.

Kilpatrick says the critics are wrong.

He and Melanson say there's no need to identify the low levels of depleted uranium that the British can find because the tests that the United States uses can detect depleted uranium 1,000 times less than what's dangerous to health.

They cite World Health Organization, or WHO, and U.S. Institute of Medicine reports as authorities, based on 50 years of health research involving uranium miners, millers and processors. The Institute of Medicine is part of the National Science Foundation and is considered the country's best impartial health research organization. Kilpatrick and Melanson also cite the recently completed Capstone study. It involved measurements of inhalable-sized particles of depleted uranium that resulted from test-range firing of the weapons into a real tank, the hulls and turrets of tanks, and other combat vehicles.

Kilpatrick and Melanson say the Capstone research got its title because officials think that it provides the last pieces of data necessary to determine the health effects of depleted uranium.

Scientists who have been working outside the Pentagon to answer that question say there are still some important pieces missing before drawing such final conclusions.

Carolyn Fulco is one of the authors of the Institute of Medicine's reports on Gulf War illnesses. She says it would not be accurate to say her organization was as conclusive as the Pentagon officials when it comes to how much depleted uranium can harm someone.

"There was almost no literature on depleted uranium," she says. Nearly all of it was on uranium before it became depleted and in circumstances very different from the possible exposure resulting from use of the weapons, she says.

As a result, the institute recommended additional study into nearly all the health questions raised by the use of depleted uranium in warfare. The WHO report says the same.

Beate Ritz is an epidemiologist at the University of California, Los Angeles, who specializes in how internal radiation sources cause cancer. She's also the primary author of several of the most recent studies of the health effects of working with uranium.

SCIENTISTS SAY SAFE LEVEL OF EXPOSURE ISN'T REALLY KNOWN

When the Institute of Medicine needed an expert to review the report that Melanson cited to support his view that the U.S. testing program is adequate, it turned to her for approval. That's because she's one of the few people in the world qualified to pass judgments of that type, Fulco says.

Ritz now sits on an advisory panel for the institute's continuing review of possible causes of the illnesses suffered by Gulf War vets.

She says no one knows what the safe level of depleted uranium is inside someone's body when it comes to cancer and risk from radiation.

The field is rife with errors and misclassifications because actual testing to settle the matter with scientific assurance is almost impossible, she says.

"When you're looking at humans, you need large numbers of subjects," to make sure that you have accurate results, she says. "But you can't cage humans and feed them uranium and count the exposure for 20 years."

The next best thing is to pick an animal - and hope that you've picked the right one, she says.

Even then, rats, mice and monkeys often have genetic and other differences that can't tell you whether a human will react the same way, she says.

So to be sure, you have to try things out on humans. Or see what happens to them after exposure.

Lots of them.

Kilpatrick, Melanson and others say 50 years of experience watching the health and health problems of people who have worked as uranium miners, millers and processors during the Nuclear Age give them the number of people and the confidence to say that enough research has been done. They point out that they add in a large margin of error to make sure they're right.

They also dismiss the idea that depleted uranium exposures resulting from combat can be a serious radiation or cancer risk.

Ritz and Alexandra Miller, a researcher at the Armed Forces Radiobiological Research Institute, say that isn't a justified conclusion, as far as science goes.

"I don't see the data that supports that at all," Miller says.

The studies on people who worked in the uranium industry are often flawed and don't involve the same issues and exposures as soldiers on the battlefield, Miller says. The Institute of Medicine's report says the same thing, and so does the Department of Veterans Affairs' educational program for physicians and other health care workers.

Using uranium industry workers' health experiences as a benchmark might not be a good measure either, say critics of the military's dismissal of the health threat from depleted uranium.

Several studies by Congress' Government Accountability Office, or GAO, note that getting an accurate picture of nuclear workers' health is difficult. That's in part because for years, the government encouraged its contractors and managers to refuse to acknowledge work-related diseases and health problems. This helped mask the true death and illness rate to researchers.

As for whether the health standards are adequate, there's also a great deal of debate. The GAO says the government will probably need to spend more than $1 billion this decade to compensate nuclear workers for health problems - a higher cost than estimated because the number of workers with legitimate claims keeps rising.

In addition, the GAO says, there's little or no scientific agreement on what constitutes an acceptable radiation risk, even among U.S. government agencies.

SCIENTIFIC MODELS NEED TESTING TO PROVE ACCURACY

Kilpatrick and Melanson say the Capstone study's data-gathering enabled them to determine how much depleted uranium dust would be inhaled in the worst of battle circumstances. They say the calculations on that volume of dust, using mathematical and other models of human health adopted by government occupational and safety agencies, prove little or no adverse health effect from use of the weapons.

Those calculations create a new standard for discussing the issue, Kilpatrick says.

Ritz and Miller say the Capstone work doesn't change the fact that there has been insufficient experimentation on animals to prove or disprove the assertions of safety.

The calculations and models that the Pentagon points to are nothing more than theory waiting to be tested, they and other scientists say.

"You know the problem with models, don't you?" Ritz asks. "You get out of them what you put in."

The type of models that the Capstone study relies on for its conclusions are frequently shown to be flawed, she says. That's much of what health science is all about - testing the models and showing whether they work.

A recent example of how these models can be flawed occurred with the chemical paraquat, Ritz says.

For decades, the U.S. government had been using it - and giving it to other countries - to eradicate marijuana and other plants used to make drugs. Critics questioned the wisdom of those programs, noting that the possible effects of ingesting the drugs were not known.

Government officials dismissed the caution warnings.

For one thing, they noted that long-established scientific models said paraquat couldn't cause brain damage because its chemical composition kept it from penetrating through a layer of cells that protect the brain from impurities in the blood.

The layer of cells is called the "blood-brain" barrier.

"All that was true," Ritz says. But just a few years ago, one of her colleagues found that paraquat could get into the brain anyway.

Like other parts of the body, the brain needs amino acids to make proteins to keep going.

The brain has special nerves to directly transfer those acids to the brain, bypassing the brain-blood barrier. Paraquat is made of molecules that look like amino acids.

So the brain sucks up the paraquat molecules, thinking that they're amino acids, she says. "And it can cause brain damage when it happens."

That's one of many examples where the models aren't good enough.

And it's why sufficient research involving human cells and animals should be done to test the models thoroughly before declaring something safe, she and Miller say.

Vernon Walker, a cancer biologist at the Lovelace Respiratory Research Institute in New Mexico, conducted a study that found that when rats inhaled depleted uranium, they developed genetic mutations indicative of cancer.

He says the government exposure standards and scientific models used to determine workplace safety - the barometers of safety used in the Capstone study - don't include the potential for developing cancer in the way that his experiments showed is likely.

The military has drugs, developed in the World War II era for troops exposed to radiation, that can reduce those mutations to safer levels, he says.

Experiments are being conducted to see whether they have the same effect on depleted uranium inhaled from the battlefield, as well as from shrapnel.

He says that based on his experiments and what he's seen from other science on the subject, he'd be taking those drugs if he were a soldier in Iraq and was exposed - especially if he were hit by depleted uranium shrapnel.

"I'd be taking the pills for the rest of my life," Walker says.

Miller says her research has found that a single particle of depleted uranium can deform cells and DNA, the basic building block of life, in ways thought to lead to cancer.

Others have shown that uranium in the body and inhaled uranium can make its way to the brain.

Those findings haven't solved the riddle of Gulf War vets' illnesses, but they're far from comforting about how safe the black dust from the explosions must be, Miller says.

Someone practicing good science shouldn't be closing the book on the subject and declaring a particular level of exposure safe under those under-researched circumstances, she says.

TOO FEW PEOPLE HAVE BEEN STUDIED TO KNOW THE TRUTH

Ritz says the same thing about the possibility that cancer risks might increase after inhalation of depleted uranium.

"Our human research, as valuable as it is, has a lot of severe limitations," she says.

At most, she says, it proves that we've been unable to detect anything, not that there's no risk.

There might be 6,000 people involved in the studies that the government is relying on, she says.

Perhaps that's enough to figure out whether something's toxic, she says, but it's far from enough to determine whether it's carcinogenic.

For cancer, if you had a million people and followed them for 50 years, you might be able to determine a safe level of exposure with confidence, she says.

But no study has ever attempted to follow uranium workers on that large a scale, not to mention people exposed to depleted uranium, she says.

After the Pentagon tested the New York reservists and announced that the soldiers tested negative for depleted uranium, a news briefing was called.

William Winkenwerder Jr., a physician who is assistant secretary of defense for health affairs, told reporters that 10 years of health studies found that "low levels of depleted uranium that our troops would be exposed to are neither a radiological or chemical health threat to our service members."

He also said there was no evidence linking depleted uranium to radiation-induced illnesses such as leukemia and cancers.

But Ritz says the failure to find a link to cancer at this point isn't surprising at all.

It will take about 30 more years before soldiers from the Persian Gulf War could reasonably be expected to start showing evidence of most cancers spawned as recently as 1991, she says.

Lung cancer - which many researchers say is the most likely form that might result from inhaling depleted uranium - would take a few years longer to show up, she says.

Some forms of leukemia and lymphomas might have started showing up in the past year or two, she says.

Those forms of cancer have also been identified as possible problems because lymph nodes are vulnerable when particles are inhaled.

Even if an outbreak of leukemia and lymphomas has begun among veterans of the Gulf War, it's unlikely that the data to prove it would have been collected and that anyone would know about it, the GAO says.

No one is comparing a list of cancer deaths in the 50 states with the names or Social Security numbers of veterans from the Gulf War, the GAO says.

And no one is likely to begin doing it anytime soon because the money has not been made available, the agency says.

NO MONEY TO TRACK VETS' CANCER RATE ANYWAY

In the past 13 years, only two studies have been financed to determine cancer incidence among Gulf War veterans, the GAO says, and both of them had limited ability to study the problem.

The studies' access to data is being curtailed as a result of financial and legal issues, the report says. Veterans in only a few states were included.

VA officials say they're studying ways to fill this gap in the data.

In the meantime, Ritz says, the best that we can do is guess what a safe level of exposure to depleted uranium might be.

Depleted uranium isn't alone in this respect.

Of all known carcinogens, "none of those in the carcinogenic fields have accepted a threshold level," where safe and unsafe can be identified with a measurable number, Ritz says.

Threshold levels are set by government agencies, not scientists, Ritz says.

"These are all policy decisions about what is acceptable," not to be confused with scientific proof, she says.

There are many critics of the military's approach to establishing safety levels and standards, but there are also many scientists who agree with how Kilpatrick, Melanson and others have handled the problem that they're faced with.

Terry C. Pellmar - who works at the same lab as Miller - co-authored the first research paper citing that depleted uranium from pellets embedded in the bodies of rats might migrate to their brains.

Still, she says, she doubts that depleted uranium is responsible for the neurological problems suffered by veterans of the Persian Gulf War. And she doubts that the government is making a mistake in the policies it's established regarding the safety of depleted uranium on the battlefield.

"As a scientist, I'm not sure of anything" that could be deemed absolutely safe, she says.

"As an individual, I would have no personal concerns."

Knowing the science as well as she does, she thinks that a soldier can trust the Pentagon's assessment of the risks.

If she were a soldier on a battlefield, she says, she would feel safe, as far as the danger from inhaling depleted uranium dust.

"We all live in a world that's filled with things that increase the chances of getting cancer," Pellmar says.

Even if Miller's research shows that a single particle of inhaled depleted uranium might increase the risk of cancer, that degree of increased risk is accepted by people all the time in everyday life. There's an increased risk of cancer if you spend time in smoky bars, she says. "Yet, we all walk into smoky bars."

Similarly, she says, there's increased risk from living in Colorado, for instance, because there's more uranium in the environment there naturally, compared with most states.

Yet thousands of people have been moving to Colorado for years.

So given the battlefield advantages that depleted uranium gives soldiers, she says, taking that little extra risk might be a good bet.