Response to a Radiation Threat

By FRAN FESI and RON RAGEN

On Monday, March 19, 2007, a Troxler nuclear moisture/density gauge, model #3430, was stolen from a parked truck on a construction worksite at 3301 Tasker Street in South Philadelphia, Pennsylvania. The theft occurred between 1430 hours and 1630 hours.

The gauge (photos 1, 2) holds a small gamma source of cesium-137 with an additional radiation source of americium-241/beryllium. When americium and beryllium are combined, they trigger a neutron emission.

1) Photos by Ron Ragen.

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2)

Many contractors, engineers, and highway departments use the gauge to measure soil, concrete, and asphalt. The quantities of radioactive material contained in these gauges are quite small, and an operator may safely use one without receiving any bodily damage from radiation. Nonetheless, the user must take precautions and care when operating and handling such gauges.

On March 20, the U.S. Nuclear Regulatory Commission (NRC) issued a news bulletin that the gauge was stolen and provided instructions on its handling if found.

On March 21, the Philadelphia Police Department’s (PPD) homeland security unit received the NRC news bulletin and forwarded it to the Philadelphia Fire Department’s (PFD) hazardous material administrative unit (HMAU). This interdepartment cooperation between the PPD and the PFD was instrumental in this incident’s mitigation from the time the bulletin was received until the property was cleared and released.

On March 22 at 0952 hours, the yellow Type A Troxler transport box was reported in a driveway, just south of 4025 Germantown Avenue. A radiological response was initiated and Deluge 59, Battalion 8, Squad 72, Squad 72A, and HazMat Task Force 1 (HMTF-1) responded.

There were three properties on the block—a church, a salvage company, and a vacant bar with apartments and a driveway. The yellow Type A radioactive transport container was found sitting in the driveway in plain view of motorists driving along Germantown Avenue. Fortunately, someone recognized the Type A radioactive container and the radiation label and subsequently notified 911.

The incident commander (IC) was Captain Gerry Prodoehl, a battalion chief (BC) working in Battalion 8. He was supported in the unified command by BC Charles Herran, the hazmat operations officer; BC Joe McGraw, head of the HMAU; and Inspector Robert Tucker, then the head of the PPD homeland security unit and major incident response team (MIRT).

The IC had Squad 72 pair up with MIRT to take radiation readings in the driveway where the container was found. The readings were consistent with normal background radiation, which comes from natural sources such as cosmic and solar rays. Persons living at sea level receive far less radiation than, say, residents of mile-high Denver. Other sources of background radiation may be certain rocks, soils, and groundwater.

Subsequently, HMTF-1 took readings in the general area, and all were consistent with Squad 72’s and MIRT’s prior readings. HMTF and MIRT took readings on the yellow Type A radioactive transport container. Readings of 40 micro-roentgens per hour (μr/hr) on the container’s surface indicated that it was empty. If the meter was in the box, the radiation readings would be as high as or higher than the “transport index” at the bottom half of the radiation label (photo 3). This box is present on radioactive Yellow II and Yellow III labels. The number shown indicates the highest radiation level one meter from the surface of the package in radiation units of milli-roentgens per hour (mR/hr). Should first responders detect any radiation above what is listed in the transport index box at a one-meter distance, they must assume that the source has been compromised. (Radioactive Yellow-II: packages with a surface radiation not to exceed 50mR/hr and not exceeding 1mR/hr at one meter.)

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Figure 1 shows the parameters for the specific labels available.

At approximately 1100 hours, representatives from the NRC and the Pennsylvania Department of Environmental Protection (PA DEP), Bureau of Radiation Protection, arrived. Both agencies assisted on-scene units with finding and identifying the radiation source.

At 1115 hours, McGraw ordered HMTF-1 and MIRT to take readings around the entire exterior perimeter of the salvage building. Readings were consistent with the normal background of 20 to 50μr/hr, except for the NRC, in which readings were above 50μr/hr. This was near a rear doorway to 4027 Germantown Avenue. These readings indicated an unknown radiation source, which would justify our entry into the building. However, we did not have to make forcible entry, because the owner was on location and gave permission to enter and search his property.

The safety officer, Captain Bill Hannigan of the HMAU, established a point of entry. Paramedics took all entry team members’ vital signs before they donned their personal protective equipment (the members’ vitals would be recorded again after they cleared decontamination). Members’ meters and dosimeters were checked to ascertain that they worked, and the background readings were documented before members entered the hot zone.

At 1238 hours, qualified radiation teams consisting of members from the HMTF-1, HMAU, MIRT, NRC, and PA DEP health physicists broke the salvage company interior (Figure 2) into four quadrants and inspected them.

They recorded readings quadrant by quadrant. There was a slightly higher reading in quadrant 2, but the team continued on to quadrants 3 and 4. When these readings were negative, the salvage company returned to quadrant 2 for a more thorough search. As the members neared a trash can in this quadrant, one of them obtained a reading of 9mR/hr. The handle for the missing meter was spotted near the top of the trash can. At approximately 1400 hours, it appeared that the meter was found. A PA DEP representative received readings as high as 30mR/hr on the outside of the container about one foot above the ground.

McGraw ordered all radiation investigation team members to exit the building after readings of 30mR/hr were found at the trash can. As the entry teams exited the hot zone, the survey team methodically surveyed them for any alpha/beta contamination.

Rob Forrest, the director of radiation safety for the University of Pennsylvania, answered our calls and advised us regarding radiation exposure levels.

John Higgins of Licenses & Inspections, commercial and industrial unit, placed a cease operation order on the property, and it remained closed until the NRC gave the approval for a certified environmental contractor hired by Underwood Engineering & Testing Co. (who was responsible for the gauge) to clean the facility and remove all radiation in the building, making the property safe.

By 1635 hours, McGraw returned all companies to quarters, except HU-1, HU-2, and HU-3, which remained on-scene while Underwood Engineering made arrangements with an environmental company to clean up.

At 1700 hours, McGraw and Tucker authorized a PA DEP representative to enter the building with Lieutenant Ronald Ragen of HMAU and Sergeant A. Buchanico of MIRT/homeland security. The entry team verified the 30mR/hr reading and took swipe tests in the building. The swipes were taken, bagged, and tested away from the hot zone. The swipes tested negative, indicating that the americium-241/beryllium sources, which are alpha and beta particle sources, were not present. At this point, there was nothing else that could be done until a cleanup contractor was hired, so police secured the property until 0930 hours.

On March 23, Underwood Engineering was contracted with Applied Health Physics to do the area cleanup. At 1600 hours, Applied Health Physics technicians arrived and took readings as high as 300mR/hr; swipe tests were negative. The technicians wrapped the damaged handle in lead and placed it in an overpack drum. The Department of Transportation requires a reading below 200mR/hr for shipping under a Yellow-III label.

The NRC representative was still concerned that there were no neutron readings. This meant that the americium-241/beryllium source was missing. So, the NRC requested a neutron search of the area. The HMTF was requested and they responded. The HMTF and the NRC representative surveyed the building from 1930 hours to 2030 hours but again did not register any neutron reading.

The lead NRC representative then notified the Department of Energy (DOE) to have a team verify that the americium-241/beryllium source was missing; the team would arrive on Monday morning. Police again secured the property.

At 0900 hours on Monday, March 26, the DOE team members arrived and surveyed the property using more advanced radiation meters. They determined that the source was not on the premises. This was a major concern, because it was a neutron radiation source and it could not be found. Once the DOE verified this, the NRC declared the building clean of radiation.

It was determined that a maul was used to break the gauge and separate the metals for salvage. There was videotape of the gauge being dropped off and brought on to the property and then the tape stops. As of June 2008, the investigation is still open and ongoing.

LESSONS LEARNED

1 Anticipate the scene growing in magnitude. Once the PFD and PPD confirms a radiological incident, our fire communication center must notify the PA DEP through the PA Emergency Management Agency (PEMA) emergency operation center. Various other agencies subsequently responded, including the Office of Emergency Management, the Environmental Protection Agency, the Nuclear Regulatory Commission, the Federal Bureau of Investigation, and the U.S. Department of Homeland Security.

2 Anticipate extended response times for agencies outside of the area. In this case, it took one day to locate a certified radiation cleanup contractor and then another day to travel because cleanup personnel were 300 miles away.

3 All responders need a basic understanding of radiation terminology and exposure values, such as the common terms micro-roentgen per hour (μr/hr), milli-roentgen per hour (mR/hr), and roentgen per hour (R/hr). Some examples of common dose and exposure values are listed in Figure 3.

4 The PFD “Radiological Incident Procedure” and its published limits for exposure are in accordance with those published by PEMA (Figure 4). All hazmat response personnel receive 16 hours of radiological response training; at least two hours are dedicated to understanding the difference between roentgens (R), milli-roentgens (mR), and micro-roentgens (μR).

5 The PFD has experienced three moisture density gauge incidents over the past three years. Following the last incident, we researched and found that there are more than 100 similar gauges within a 100-mile radius of Philadelphia. As a result, soil density gauges are now included in our radiological response training. Two excellent resources are www.troxlerlabs.com and your state DEP, Radiation Division. Call and ask for a list of moisture density gauge users in your area, just to get an idea of how many there are.

6 When thieves have selected a target, pretty much nothing is going to stop them. As with any piece of equipment, all you have to do is let your guard down one time and that moisture density gauge is gone. Gauges are reported stolen or missing regularly.

FRAN FESI is a 35-year veteran of the Philadelphia (PA) Fire Department (PFD), working in both engine and ladder companies. He has taught “ladders” to five cadet classes at the Philadelphia Fire Academy and then became the hazmat training coordinator for the PFD. He is also a certified firefighter I and II, instructor I and II, hazmat technician, and state-certified suppression instructor.

RON R. RAGEN is a 24-year veteran of the fire service and a lieutenant with the Philadelphia (PA) Fire Department, Haz-mat Administrative Unit. He graduated from Holy Family University with a bachelor’s degree in fire science and public safety.