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SANDIA LAB NEWS

Lab News -- Oct. 14, 2005

October 14, 2005

LabNews 10/14/2005PDF (650KB)

Sandia researchers determine that common anthrax sampling methods need improvement

By Chris Burroughs

Inaccurate sampling of biological pathogens can be deadly.

That’s what Sandia researcher Gary Brown (6245) and his team discovered after a year-long Department of Homeland Security (DHS)-funded study where they looked at sampling processes used to determine the number of viable organisms existing on surfaces following a biological attack with agents such as anthrax.

“We evaluated Centers of Disease Controls (CDC) recommendations for sampling methods and discovered that all current methods underestimated the number of spores, such as Bacillus anthracis, the organism causing anthrax, actually present on surfaces,” Gary says. “The sampling methods are much less effective than anyone realized.”

Miscalculating the number of spores present following an attack could potentially be lethal.

The idea for the sampling study dates back to the fall of 2001 when letters containing anthrax bacteria were mailed to several news media offices and two US senators, contaminating numerous postal facilities and killing five people. Critical questions became 1) how efficient are the various methods used to sample amounts of spores,

2) what minimum amounts of spores have to be present if anthrax is to be detected by these methods, and 3) how effective are the various methods for extracting material from samples for analysis.

Gary became involved in the study as part of a DHS-funded Domestic Demonstration and Application Program, led by Mark Tucker (6245), that was investigating the restoration of major transportation facilities in case of a bio attack.

“If a bio attack occurs, we need to be aware of how many anthrax spores exist initially and how many remain after a cleanup,” Gary says. “No one knows how effective these cleanup methods really are, and you don’t want to leave material around after a building cleanup in concentrations capable of causing infection.”

The question of “how clean is clean” is important for many biological and chemical agents, not just for anthrax. It has received congressional attention and is an area in need of significantly greater study, he adds.

The study’s objective was to provide a robust scientific and statistical evaluation of current swab, wipe, and vacuum surface sample collection methods. The investigation was intended to empirically determine recovery efficiency and extraction efficiency, calculate collection efficiency, and determine each method’s limit of detection.

Reference surfaces of coupons were seeded by dry deposition with a mixture containing Bacillus atrophaeus spores (a bacteria similar to anthrax but not toxic) and silicon dioxide particles. Forty-eight coupons, each measuring 1.25 cm x 5 cm and made from stainless steel or painted wallboard, were used as the reference surfaces.

After seeding, the surfaces were sampled using traditional collection methods — swabbing, wiping, and vacuuming. The sampling team found that none of the sampling methods was very efficient. The swab system collected 40 percent of the spores, leaving 60 percent behind. The wipes collected 28 percent, leaving 72 percent on the coupons.

The biggest surprise was that the vacuum method collected only 20 percent of the spores, leaving 80 percent on the surface.

“Before this study, the vacuum method was the most highly recommended sampling method by the CDC,” Gary says. “As the result of our study CDC no longer recommends that method.”

The study also showed that each collection method has its own detection limit. Through the swabbing technique, 125 spores must be present on the surface to obtain a positive culture. Five hundred spores must exist before a positive culture is observed in both the wiping and vacuuming methods. The current EPA clean-up criterion is no positive cultures from environmental samples — meaning a site may be cleared because no samples were positive, but viable spores may still remain.

The most widely accepted estimate of inhaled spores required to produce a lethal dose in 50 percent of the population is 8,000. However, researchers at the University of Texas Medical Center using “probit” models, estimate that only 98 inhaled spores may cause lethal infection in 10 percent of the population.

Gary says the study will probably result in significant changes in the interpretation of environmental sampling data following another anthrax or similar bioagent event. It will also be useful in determining if a facility has been decontaminated following a natural disaster, such as ongoing efforts associated with Hurricanes Katrina and Rita where naturally occurring coliform bacteria and pathogenic mold, like Aspergillus and Stachybotrys species, are of concern.

“If there is a future release of anthrax, the current sampling methods would still be used, but they would be interpreted differently,” he says. “In the past if no spores were detected, it was generally considered that the surface was decontaminated. But now we realize that spores may still be present in numbers capable of causing infection, resulting in a public health response that would most likely be cautious.”

Also, if the analysis is positive, the probability of a public health threat with potentially large numbers of infection is high, and the public health response would be more aggressive.

“Either way, with current surface sampling methods, a public health threat following release of bio-threat agents cannot be ruled out,” Gary says. -- Chris Burroughs

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Remotely controlled guns guarding Y-12 high-security sites

By John German

At the NNSA’s Y-12 complex in Tennessee, automated gunmen are pulling guard duty at some of the site’s most secure facilities. The robotic gun turrets are controlled remotely by security officers from the safety of a control room.

Sandia developed the Y-12 systems, called Remotely Operated Weapon Systems (ROWS), in partnership with Precision Remotes Inc. of California, which invented the systems.

The work was done for DOE’s Office of Security and Safety Performance Assurance to create automated defense systems to help human security officers protect DOE and NNSA high-security facilities and high-risk materials from armed adversaries.

Sandia’s job was to modify the systems for NNSA applications and evaluate the systems in security settings against mock adversaries, says 6422 Manager Steve Scott.

Each ROWS uses a suite of electronic linear actuators to quickly and precisely aim automatic or semi-automatic rifles at a target. It is commanded remotely by a person in a control station using cameras, scopes, and other sensors.

Unlike a human, the ROWS doesn’t get fatigued, and its accuracy isn’t affected by tremor, trigger anticipation, gun recoil, or shooter fatigue. Its accuracies approach and sometimes exceed those of the best human snipers.

Out of harm’s way

Because ROWS is controlled remotely by someone who isn’t in the line of fire, better decisions can be made about when to shoot, says Steve.

“It removes some of the stress of the situation, which leads to better decisions,” he says.

Other advantages include the ability to respond to multiple threats and locations from one command center; immunity of the system to biological, radiological, chemical, and other environments; and increased firepower with reduced costs. For safety, two people are required for operation of a ROWS system.

During evaluations at Sandia, developmental ROWS systems were installed at Sandia locations, and trained operators practiced using them against a variety of threats and scenarios.

Sandia also modeled use of ROWS systems on the Joint Conflict and Tactical Simulator (JCATS), a computer program that estimates the delay imposed on an adversary by an added security feature.

In many of the simulations, ROWS systems improved the accuracy of the operators and provided additional delay, giving human responders a better chance at stopping or repelling their adversaries, says Steve.

The Y-12 system is the first deployment of a ROWS system in the nuclear weapons complex. Sandia is assisting in the development of ROWS for DoD applications as well. -- John German

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Exercise missile ‘accident’ shows nuclear readiness by Sandians

By Neal Singer

An explosion on a Navy loading dock destroyed one Tomahawk missile and dropped a second into 15 feet of water, where it lay buried in mud. Was the water contaminated by radioactive materials? Were air or land contaminated by the plume from the explosion, caused moments earlier by the crash of a small private plane into the dock?

Those questions formed the basis for the elaborate six-day scenario — only partly simulated —that drew 20 Sandians and a number of government agencies to the Navy’s Kings Bay submarine base at the southern end of Georgia for an exercise called Dingo King ’05 from Aug. 22-26.

Real — except for the explosion

The exercise was real except for the initial dock explosion that precipitated the problem. Also, nuclear warheads had been removed from the Tomahawks.

Participants worked 12-hour shifts — some in cumbersome personal protective equipment — in intermittent rainstorms, air thick as soup (daily humidity: 90+ percent), heat in the 90+ degree range, and Hurricane Katrina on the horizon still deciding whether to proceed up the Atlantic coast or enter the Gulf. The melded teams found, raised, dismantled, and prepared the “disarmed” missile for transport to a safe haven.

The exercise revealed the strengths and weaknesses — both bureaucratic and naturally occurring — of the massive attempt at coordinating numerous government agencies to achieve a common task. Most participants at a so-called “hot wash” after the exercise pronounced the exercise an overwhelming success, despite real-world glitches that had to be overcome.

For example, a crucial team called the Accident Response Group (ARG), populated by Sandia (for this exercise, six full-time and 14 volunteer employees), Los Alamos, and Lawrence Livermore national laboratories, and Pantex participants arrived a day late on the scene because a charter plane provided by Ross Aviation — the company contracted to fly the team to an airport in northern Florida — developed real-world problems and could not take off. The team was ferried across the country the next morning by a different carrier.

The delay in arrival of the 70-member main technical group not only slowed work on recovering and safing the weapon but created unease in media simulated at the exercise site. Reporters were frustrated at being unable to get their more technical questions answered by Navy divers or high-ranking Navy players. (Unexpectedly, the most penetrating questioner among the simulated media was Rear Admiral Annette Brown, Commander of Navy Region Southeast, who for 10 minutes played the part of a local reporter.)

On the positive side, the exercise showed that talented people with different protocols could work together. “We felt very welcomed by our Navy hosts,” said DOE site leader Debbie Monette, assistant NNSA manager for national security. That feeling was corroborated by every Sandian that the Lab News interviewed.

One reason for the ready integration, said Tom Laiche, health physicist and manager of Hazardous Waste Management & Lab Services (10334), was that “The EOD [explosive ordnance disposal] military guys were anxious to have the engineers there to explain to them what was happening technically.”

Focused on ‘what goes boom’

The EOD folk, he said, are focused on “what goes boom and how to keep that from blowing up. They know rocket motors, propellants, explosives. They’re not necessarily conversant with the heavy metals, neutron generators, and other specialty inclusions. The radioactive portion may be a little unfamiliar to them.

“Meanwhile, the Labs engineers know what makes it work but they’re not the experts in handling explosive materials.”

Recovery procedures necessarily contrasted with popular movies showing superheroes quickly recovering buried treasure as soon as they find it. Navy divers, having located the missile on their third attempt, needed to develop and present a safe retrieval plan and have it approved before proceeding. This was not, after all, pieces-of-eight but (in exercise terms) an extremely dangerous device. The lift plan was written in tents cooled by five-ton air conditioners brought by the ARG, and then transmitted via broadband fiber optic lines laid by the ARG to temporary headquarters three-quarters of a mile away.

Pressurized water was pumped by a hose through the Bay water to blow off enough mud to insert a strap under one end of the missile and lift it slightly. More high-pressure water cleared off more mud, another strap was inserted and the missile raised higher, steadily overcoming the resistance of the vacuum created in the muck as the weapon lifted.

Connecting real world to ‘hot zone’

Because the potential for radiological disaster was huge, the ARG team brought monitoring equipment and the expertise of nuclear designers who knew exactly how the weapons functioned.

Four on-foot Sandians deployed 3,100 feet of fiber optic cable to link four video cameras in the “hot zone” proscribed to most participants to the command-and-control center.

“It’s a means of connecting the real world to the hot zone,” said ARG member Dave Tenario (12345), who said that fiber was preferred over copper or radio broadcast because there was far less chance of detonating the high explosives.

The portable integrated video system — a key piece of the equipment that Sandia developed — went dark when a vehicle drove over a cable. But the ARG quickly located the problem and got back on line.

“These are all real-world problems,” said first-time participant Brad Mickelsen, manager of Nuclear Safety Assessment (12332), “and we overcame them.”

Speed, he said, was less of an issue than moving without making critical mistakes.

“I think the ARG shined, from a tech expertise perspective. We’re well-respected in the accident community. Our role is significant. From a larger perspective [we field] 75 to 100 people who know their jobs well, not counting people back home supporting us.”

Sandia maintains most ARG gear

Sandia, under the leadership of John Hoffman of Emergency Response System Engineering (12345), maintains the bulk of ARG equipment for all users year round, and is responsible for seeing it gets to emergency sites in a timely manner to help the multi-agency ARG.

Why wouldn’t the Navy divers try to locate the missile — known to have fallen close by the dock — by merely poking in the mud with a stick? “If I poke it, I have to worry about it,” Brad said. “I don’t know how much I’ve sensitized [the high explosives in the weapon].” He said the divers probably used magnetometers to locate the shell of the missile.

Interdepartmental problems occurred when a control line set up by Pantex employees, beyond which authorized plans were needed, ran afoul of Marines attempting to relieve their buddies at a shift change in the designated hot zone area. As the Base nuclear commander later put it, “The Marines did what Marines do,” and cleared the area. For an hour and a half, they would let no participant in. The problem was solved via DoD and DOE discussions and rapid communication to the front lines.

Other failures in communication were noted, as when already-used and thus potentially frayed straps were employed instead of fresh ones to lift the heavy missile out of the mud and lay it on the dock.

Exercise just a step ahead of Katrina

Still, overall coordination was rated by many participants as “exceptionally good.” Members of the ARG were rapidly accepted and integrated with their DoD opposite numbers. Members of the two huge departments, along with participants from FEMA, the FBI, the Defense Threat Reduction Agency, Environmental Protection Agency, National Transportation Safety Board, the National Nuclear Security Administration, and others cooperated to develop plans, lay out work areas, transmit information, and remove, disassemble, and package dangerous objects.

Mission accomplished, the ARG lifted off in a charter plane nonstop to Albuquerque on

Saturday, six days after activation. The lift-off on

Saturday afternoon was a step ahead of Hurricane Katrina, which had by then veered toward New Orleans.

Visible in the distance and as high as the plane, the hurricane loomed over the normal cloud layer below like the Sandias over Albuquerque. The next morning, it would strike New Orleans, finding terrible gaps in its preparations, despite the city’s FEMA exercises.

To the natural question of how effective the DOE/DoD exercises would be in the event of a real emergency, Tom Laiche responds, “From a purely weapons recovery standpoint, the national labs and the military, teaming together, have exercised together enough that we can recover about any kind of weapon in any kind of configuration.”

The problem he foresees, however, is showing “an immediate and positive reaction to public issues that will be generated.” By this, he doesn’t mean a media presence so much as “immediate government assistance, and people out there doing things.” From a health physicist’s point of view, he says, “I could tell them to go to sleep and don’t worry about it. But from their point of view, their dog will have died, children break out in hives [and they’ll attribute it all to the accident] — it’ll be another Three-Mile Island. If we have a release of radioactivity from a true weapons accident, it will take us a long time politically to recover.” -- Neal Singer

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