Radiation levels detected at an old Biggs Airfield bunker were nearly seven times higher than established acceptable safe levels, according to a U.S. military report obtained under the Freedom of Information Act.
The U.S. Air Force Safety Center prepared the July 3 report for Fort Bliss titled, "Trip Report, Inspection of Former Air Force Weapons Storage Area (WSA), Biggs Army Airfield."
During a site visit in June, the Air Force inspectors took alpha and beta particle readings in a storage igloo or bunker (Building 11507) with two devices, a Ludlum Model 2360 meter and a Ludlum Model 43-89 probe. They also conducted complex calculations, and applied estimates that the inspectors described as "conservative."
Inspectors said they found high levels of uranium activity concentration levels at location "Painted 3."
"This level is in excess of the acceptable maximum level in (Atomic Energy Commission) Regulatory Guide 1.86 for uranium isotopes," the report said.
The contaminated bunker is in the Snake Pit area at Biggs Airfield, roughly north of Fred Wilson and east of Railroad Drive in Northeast El Paso.
"The radioactivity of the painted site on the floor of Building 11507 was estimated in the report to be contaminated at a level almost seven times greater than is considered
acceptable," said John Walton, an expert at the University of Texas at El Paso who reviewed the figures for the El Paso Times. "Some of the initial contamination has been removed over time as the paint wore off the floor."
Overall, "this is not huge, but the danger from radiation depends on how long you've been exposed to it," Walton said.
According to the National Institutes of Health, radiation poisoning symptoms may include bleeding from the nose, gums, mouth and rectum, open skin sores, ulcers in the esophagus, stomach or intestines, skin burns, weakness and bloody stools, among others.
"Exposure to enriched uranium is harmful when it is inhaled into the lungs or ingested," said Walton, who speculated that "workers might have tracked small contaminated paint chips home where they were eventually inhaled or ingested. Most likely, this would have resulted in a very small and limited exposure of soldiers and their families over the past 50-plus years."
He also said, "Generally, it takes thousands of years for uranium to reach the groundwater given the depth of groundwater in this part of El Paso. In the desert, windblown dust can be a greater problem."
The Air Force report stems from a site inspection June 26, which was prompted by a tip from a former Air Force nuclear weapons maintenance technician who was concerned that potential development and construction in the Snake Pit area could expose people to radiation poisoning.
A second veteran also provided details that helped the safety inspectors locate the igloo/bunker that the Air Force Strategic Air Command formerly used to store and maintain unsealed nuclear weapons from 1955 to 1959, according to the report.
The Air Force "maintained early-design, unsealed nuclear weapons from 1955-1959 at Biggs AFB," which contained enriched uranium, the report said. "Enriched uranium is highly radioactive uranium.
"After that time, the (Air Force) would have only maintained sealed-design nuclear weapons," the report said. "Though the Air Force ceased fielding unsealed nuclear weapons in the mid-1960s, the Army had a stockpile of unsealed weapons well past this time."
Air Force inspectors found most of the contamination on the paint of the floor of the 300-square-foot storage igloo or bunker. The epoxy paint, which has deteriorated over the years, was used in the past to contain radiation.
A former airman who served at Biggs from 1956 to 1959 recently told military officials that "uranium oxidation was removed from fissile capsules at work stations outside of the vault, but within both C-structures (buildings 11507 and 11513)," the report said.
Back then, during one incident, the report said, "an excessive amount of uranium oxidation came off one fissile capsule during maintenance, which caused an area of contamination on the floor. To mitigate the contamination, the contaminated floor area was covered with a layer of paint."
The report said, "Igloos with (Air Force weapons storage areas) were commonly used for storage of the bomb assembly sections of early, unsealed nuclear weapons and later complete sealed nuclear weapons."
Fort Bliss officials said the Army Environmental Command is looking for areas near the contaminated bunker where sealed containers of radioactive residue might have been buried.
Such deposits are believed to contain rags or other items used to clean nuclear weapons that were housed in the bunker during the 1950s and 1960s.
One of two former Air Force workers told officials that the containers with waste were buried in a drilled hole about 12 feet deep and 18 inches in diameter, and covered with dirt.
A satellite image attached to the report shows two areas that were circled where officials suspect the containers might be buried based on what the former Air Force worker remembered.
The report has pictures of the bunker interior that show steel storage shelves, a high security vault door, and the painted areas where special measuring devices detected the radiation contamination.
The former Air Force Weapons Storage Area at Biggs includes eight storage igloos or bunkers, two C-structures, and the slab remnant of a former structure (Building 11508).
After the Air Force turned Biggs over to the Army in 1966, Fort Bliss reactivated the airfield in 1973 and began using the bunkers to store and issue conventional training weapons.
Walton said the former Air Force worker is to be commended "for coming forward as a potentially serious problem has been averted. New construction might have unearthed the burial site, leading to widespread dispersion of the contamination."
"Finding the precise location of the burial site and cleanup of both contaminated areas to meet modern standards will be expensive but is feasible," Walton said.
The 2013 Air Force Safety Center report said that similar surface contamination was found in former Air Force Weapons Storage Areas at Carswell AFB (Texas), Medina Base (Texas) and Bunker Hill AFB (Indiana).
At Bunker Hill, the report said, "the contamination was attributed to the handling of accident debris from a 1964 nuclear weapons accident, while for Medina Base, the contamination had the potential attribution to a 1963 nuclear weapons accident on the installation, when the AEC (Atomic Energy Commission) was responsible for the site."
The Carswell AFB contamination could not be attributed to incident or accident, the report said.
Walton said pre-1960 nuclear weapons had unsealed enriched uranium that oxidized (rusted like iron or steel) over time in the triggers.
"Modern nuclear weapons have the trigger sealed inside a metal container," Walton said. "This improves safety, security, and longevity of the weapons. Modern nuclear weapons do not leak radioactive materials."
Fort Bliss officials said the Army's investigation into the extent of low-level contamination in the Snake Pit area is ongoing. The Army post also set up a hotline to handle questions about the contamination.
Anyone with concerns about radioactive contaminants is asked to call a 24-hour hotline: The numbers are 744-1255, 744-1962, 744-8263 or 744-8264.