Depleted uranium, as much as 600 pounds, is thought to be in the ground at several sites from training shells fired in a 1960s classified program to give soldiers a nuclear- tipped bazooka called the Davy Crockett, according to Army documents. The training rounds were smaller spotting shells to train crews on the use of the atomic weapon without the big boom and a mushroom cloud. The Davy Crockett was never fired in combat.
Since discovering the uranium munitions in Hawaii in 2005, the service has done 10 years of detective work to figure out which bases participated in the testing program.
The Army says 12,405 acres may have been contaminated during the Davy Crockett days. Fort Carson is joined on the roster by installations in Hawaii, Washington state, Georgia, Kentucky, Kansas, Louisiana, North Carolina, Texas, Oklahoma, South Carolina and California.
Fort Carson says no depleted uranium was found during post inspections, which included use of radiation detectors. But poor record keeping in the 1960s leaves the issue in doubt.
It is known that troops trained with the weapon at Fort Carson. And training, the Army's Installation Management Command in Texas surmised, likely left depleted uranium residue -- a low-radiation byproduct of uranium enrichment for reactors and weapons.
"The Army's position is that the Army fired the M101 spotting round from the Davy Crockett weapons system at Fort Carson," Army Installation Management Command spokeswoman Cathy Kropp said.
The Army says cleaning up the waste at Fort Carson and other installations is too expensive -- the cost is estimated at more than $300 million nationwide and $25 million in Colorado.
So it is asking the federal nuclear watchdog agency for permission to leave the waste where it may have been for 50 years -- in the soil of Colorado and 11 other states.
There is no risk to the public or to soldiers, Fort Carson radiation safety boss Ben Hutchinson said. Even close contact with the uranium is no cause for fear, he said.
"You can handle it with your bare hands and it's not going to hurt you," he said.
The Pentagon has argued for decades that depleted uranium is nearly harmless. Once in the soil, it stays there and poses little risk to the public, the Army says.
"The Army anticipates the potential for incorporation into flora and fauna, including the likelihood of any pathway leading to an impact on human health and safety, to be minimal," the Army said in its permit application to the nuclear agency. "In general, this conclusion is based upon both biosphere modeling and actual flora and fauna sampling at Army installations."
A series of university studies of depleted uranium have shown that if it's inhaled or ingested, it can cause health problems, including cancer, birth defects and kidney failure. Some studies have linked depleted uranium ammunition used during the 1991 Persian Gulf War to Gulf War Syndrome, an umbrella diagnosis for maladies afflicting veterans who served in Iraq and Kuwait.
Starting with the Manhattan Project in the 1940s, scientists have made depleted uranium for years as they sought to make hotter isotopes for bombs and reactors. The uranium that goes boom -- mostly U-235- is stripped from its less reactive counterpart, U-238, in the process. Until the 1950s, the low-radiation U-238 was considered waste. Then the Pentagon found ways to use it in the construction of conventional weapons.
A 1961 report on the Davy Crockett program shows that about 7 ounces of depleted uranium was used in each training round. The Army estimates that more than 1,400 of the training rounds could have rained down at Fort Carson; none have been found.
In 1961, the Army said the training rounds posed no environmental or health risk.
For safety, "standard operating procedures as exercised in the use of any conventional weapon will be adequate," the Army said in a report to the Atomic Energy Commission, a predecessor to the nuclear agency.
University of Colorado at Colorado Springs physics Professor Tom Christensen said all forms of uranium bring some level of risk.
"Uranium is uranium is uranium is uranium," he said. "The problem with depleted uranium isn't radiation. It's a toxic metal."
Hutchinson said Fort Carson tests show no apparent leaching of depleted uranium into groundwater or air.
He said the only way someone could be hurt by depleted uranium is unlikely.
"Who is going to walk out there, pick one of these up and eat it?"
Burying the past
At sites near Turkey Creek and at an artillery range in the center of the 135,000-acre post, the Army plans to post signs saying "Caution Radioactive Material."
Another area where the depleted uranium rounds could have been used is next to the hospital and near buildings that house the 10th Forces Group. The Army says research shows that just three rounds were fired in that now-populated area off Titus Road, so no signs will go up.
The Army said the total waste at the post is thought to be minimal, although a cost estimate for cleanup said the service would have to remove 969 55-gallon drums of contaminated soil and weapon fragments from areas covering nearly 1,200 acres.
Steven Brown, a nuclear safety expert from Denver who has worked in the field for 45 years, says the Army is following well-used protocols for dealing with the problem.
"The first step is isolate and contain," Brown said during a break from a United Nations conference on nuclear safety in Australia last week.
The second step in most nuclear waste situations is called "characterization." That's figuring out exactly what you have and where it's located.
The Army has told the NRC it won't do that because the move would require digging up training ranges.
"The evaluation of Army records and the estimates used to determine the amount of DU present is complete," Army nuclear safety boss Bob Cherry wrote in a letter to nuclear regulators. "The Army has no plans to perform physical measurements."
Kropp said the rounds were fired on training ranges where soldiers don't tread, so there's no need for digging.
"The Army really isn't considering it an issue," she said.
Atomic coming of age
In an era when the Air Force and Navy fielded thousands of nuclear warheads, the Army joined the arms race with "tactical weapons." These baby nukes were designed for battlefield use rather than to annihilate cities.
The diminutive Davy Crockett was the smallest, weighing just over 50 pounds. The Washington, D.C.-based Brookings Institute said the nuclear warhead that could be launched by the Davy Crockett was "two to four times as powerful as the ammonium nitrate bomb which destroyed the Alfred P. Murrah federal building in Oklahoma City."
The weapon system was tested once in a 1962 Nevada blast dubbed "Little Feller." That was part of an Army training exercise that involved 550 troops simulating how the weapon would be deployed in war.
Troops, though, couldn't use nuclear warheads in training, so they fired the smaller depleted uranium "spotter round." Now, use of depleted uranium at U.S. bases has been strictly regulated -- it is not used outside combat.
An Army manual gives step-by-step instructions in how to keep troops safe when dealing with depleted uranium.
"Heavy metal poisoning is the main health concern associated with DU," it says.
But in the 1960s, that manual didn't exist, and few people knew that the training rounds contained uranium.
"The Davy Crockett weapons system, including the M101 Spotting Round, was classified in the 1960s, and records of its use were closely guarded," the Nuclear Regulatory Commission said.
Retired Army Col. Dave Hughes of Colorado Springs remembered the dawn of the Davy Crockett. Army leaders saw it as the best way to save Europe from a massive Soviet attack. For Fort Carson's biggest unit, the 5th Infantry Division, the weapon was seen as a soldier's best chance to survive a war with the Soviet Union.
"I was perfectly intrigued with the small nukes," he said.
Hunting for waste
Because the program was so secretive, Army environmental scientists had few clues to where waste could be found at installations. Fort Carson officials say one map identified a Davy Crockett range; detective work led to two other sites.
Hutchinson said he learned the spotting rounds could be at Fort Carson in 2008, when Army researchers found evidence in archives.
It's known that the Army ordered 2,100 nuclear warheads and 75,000 depleted uranium training rounds in the Davy Crockett program.
More than 30,000 of the training rounds were fired nationwide.
At Fort Carson, the Army says preliminary searches, including the use of Geiger counters to track radiation, yielded no trace of the nuclear waste. They found radiation, but Army officials say that's expected in Colorado, where the soil contains above-average levels of uranium.
Searchers did find other residue, though, that indicated the Davy Crockett was fired in training from 1962 to 1966, Hutchinson said.
Hutchinson, who has worked at the post since 2003, led researchers on a tour of the Fort Carson impact area -- one of the three suspected depleted uranium sites -- where artillery and mortar rounds have fallen for generations.
The cratered landscape is full of unexploded munitions and other hazards.
That means any depleted uranium in that 247-acre plot where researchers suspect the Davy Crockett training rounds hit will remain undisturbed for the foreseeable future, he said. And since the discovery of possible depleted uranium, the Army has banned firing into the sites to ensure what's in the ground stays there.
No public debate
Plans for Army construction, training and helicopter landing sites have been hotly debated in recent years. Unless something changes, its nuclear waste plan will not.
Public comments on the Army's nuclear waste plan are not being entertained. No public hearing to air grievances is planned. No environmental impact statement will be filed.
That's because the Army and the nuclear agency invoked the provisions of federal regulations that allow discussion of "possession, manufacturing, processing, shipment, testing, or other use of depleted uranium military munitions," to occur outside the public eye.
The public can object to that finding and fight for a hearing, through an electronic filing process outlined here: http://1.usa.gov/1RaYxQ3.
In short: If you want a hearing, hire a lawyer and file your objection by Nov. 4.
The regulations say the public must prove it faces harm from the Army's proposed permit and must have a legal basis to fight it.
The Army also hasn't gone out of its way to tell neighbors about the nuclear waste that could be buried on the post.
Local officials, including Colorado Springs Mayor John Suthers, said they've never heard of Fort Carson's nuclear dilemma.
The same is true in Washington where the state Department of Ecology says it hasn't been notified of possible depleted uranium at Joint Base Lewis-McChord or at the Yakima Training Center.
"We're going to be very interested in this going forward," said Seth Preston, a spokesman for the Washington agency.
As far as the Army's decision to keep the nuclear waste on training ranges, even the Nuclear Regulatory Commission has little power.
Federal law exempts the Pentagon from many commission rules.
"We do not have authority to tell the Army they must clean this stuff up," Conley said.
Neither does the Colorado Department of Public Health and Environment.
"That is not something our radiation program regulates," said Warren Smith, the state agency's community involvement coordinator.
Kropp said the Army has no need to discuss the environmental impact of the depleted uranium because it has been there for decades. She cited the same reason for why the depleted uranium wasn't discussed in a series of Army environmental studies at Fort Carson over the past decade.
"We didn't think there would be impact on the land use," she said.