We’ve written before about how radiation is often overlooked, yet unsecured radioactive sources can lead to catastrophic scenarios for law enforcement, emergency response teams, and the community. One type of equipment that is often omitted from radiation preparedness plans are nuclear density gauges.
Density gauges are used to measure variations in the density of materials and are often found in the concrete, construction, oil and gas, petrochemical, chemical, food and beverage, and general process industries. There are high-performance non-intrusive, non-contact nuclear density gauges that can accurately measure the density or percent solids of a liquid or slurry in a pipe for any application that may involve a high temperature, highly toxic or highly corrosive process. This technology helps to ensure accurate process control and optimum productivity during mining processing, petrochemical transportation, coal operations, food processing, water treatment, dredging, and pulp and paper operations.
There has arisen a safety and security problem involving these nuclear density gauges, however. They are getting stolen.
One FBI representative reported that there have been over 100 reports of theft or loss of density gauges over the last 2 years. Some of the gauges are getting stolen because thieves think they are expensive pieces of equipment they can pawn, but others are stealing them to sell the nuclear source on the open market.
USA Today reported in April that a Phoenix Police Department SWAT team arrested a man at his apartment on suspicion of stealing three density gauges containing radioactive material from his workplace. The gauges were used to survey asphalt and other materials for cracks. In February, the Jackson County, Mississippi, sheriff’s office was searching for a stolen gauge from a Department of Transportation work site.
This past summer was a banner season for gauge thieves. A radioactive gauge was stolen from a construction site in Denver at the Colorado School of Mines. There were two stolen nuclear density gauges used to determine soil compaction in Las Vegas. In addition, Connecticut State Police had to track down a gauge used to test soil density that was stolen along with the vehicle of a lab employee, who had the gauge in the vehicle’s trunk.
The ctpost.com article noted that “any attempt to tamper with the radioactive sources in the device could subject someone to radiation exposure. (Density gauges can contain small amounts of radioactive cesium-137 and americium-241.)
Any handling of unshielded sources outside the container could carry a risk of potentially dangerous radiation exposure.” Luckily, in this instance the thief was found and arrested, and nuclear inspectors are reviewing the case. In the Phoenix case, the suspect surrendered, and officials found no radioactive material had escaped the gauges.
The actual Americium 241 source used in these gauges is about the size of a pellet and is, of course, radioactive. The USDA Office of Homeland Security and Emergency Coordination Radiation Safety Division has outlined several requirements for securing a gauge, and what to do if it goes missing:
“…Always maintain the gauge under constant view and immediate control when it is not in storage. At job sites, do not walk away from the gauge when it is left on the ground even if it may seem safe to do so. Protect yourself and the gauge from the danger of moving heavy equipment. Always keep unauthorized persons away from the gauge.
When the gauge is not in use at a temporary job site, it must be securely locked in the operator’s vehicle (or other appropriate locked storage location).
Theft or Loss
As soon as it becomes known that a nuclear gauge has been stolen, lost or, misplaced, the Permit Holder, or the individual in possession of the nuclear gauge, must immediately call the Radiation Safety Division for assistance. Finding the gauge must be an urgent priority, which may involve law enforcement and the resources of the NRC.
If you have density gauge instruments at your workplace, you should of course make keeping them secure a high priority. However, local officials should also have a plan in place in case they become a threat to public safety. When these instruments are lost or stolen, officials must be able to monitor, detect, and respond.
Since many law enforcement agencies are aware that a radiation preparedness plan is necessary, but they don’t know where to begin, we’ve outlined five steps that every law enforcement agency should consider. Below are the steps, but read the full document to get more details. (You can download the 5-Step Radiation Preparedness document here. )
- Step 1: Recognize the importance of preparation.
- Step 2: Develop a coordinated, smart program.
- Step 3: Determine funding sources
- Step 4: Identify instrumentation and a vendor with solutions to match your needs.
- Step 5: Train agents and implement your plan.
There are no shortcuts to preparing for the most dangerous scenarios that impact public health and safety. But being prepared is the first step in keeping the public safe from what may have previously been an overlooked threat in the community.