Securing Radioactive Materials: A Guide for Researchers & Labs
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Securing Radioactive Materials: A Guide for Researchers & Labs

By Dr. Zoomie

Hello, Dr. Z – We got an inspection the other day and I was told I need to beef up our security program and they said something about “IC levels” (or something like that). I’m a professor who happens to use radioactivity for my research – what do I know about security? Can you give me some pointers…or at least tell me where to start? Thanks!

Well…you’ve got your work cut out for you. I can get you started, but I’ve got to admit that I’m not a security expert. So I can point you in the right direction, but at some point you’re likely to need to ask for outside help from your local police precinct, your corporate security officer, or someone else. But let me see how far I can get you.

Let’s get started with the obvious – why you (and more importantly, your boss) should care. And the reason for this is that it’s important to your inspectors and because it’s the law (specifically, 10 CFR 37 So let’s start there.

What 10 CFR 37 says (in greatly simplified form) is that you are required to take appropriate steps to make sure that the radioactive materials under your care cannot be lost or stolen. The easiest way to phrase this to your boss is “God help us if there’s a dirty bomb attack…and the investigators find out that our radioactive materials were the ones that were used.” That’s going to open you up to all sorts of regulatory trouble – and possibly to even more problems from lawsuits. I should say, too, that there are two things to be aware of. First is that, if you possess “increased controls” (or “IC”) levels of radioactive materials then you are required to take a number of specified security measures to try to secure them as well as possible. The second is that, in addition, you’re required to take reasonable measures to secure all of your radioactive materials against loss or theft – even the tiny little sources that don’t pose a risk to anyone. Or, the way I phrased it in my radiation safety training, “Nobody should be able to walk in off the street and walk away with radioactive materials from any lab or storage area.”

What this means in practice is that you’re likely to have multiple features and practices in place – and that you’re going to have to check and test them from time to time. For example – if radioactive materials are in use by a qualified radiation worker then it’s likely that they won’t be stolen. But if that worker leaves the lab (or clinic) without securing the radioactive materials then the security has been compromised. So then you need to train your radiation workers to put their radioactive materials into a safe, locked refrigerator, or some other secure location if they need to step out of the lab for some reason. A secure location might simply be a locked refrigerator, a safe, or even a locked room – as long as it’s somewhere that a non-radiation worker cannot access. But you can also just lock the door to the room – or lock the door to the lab suite, or even lock up the entire floor or building. Here’s what that means in practice.

Say you keep your radioactive materials in a “hot lab,” including over lunch and during breaks when the lab is empty. That’s OK – as long as nobody leaves the door open at any time. As long as the lab remains locked, the materials are secure. But…if you (or anyone else) ever leave the door even slightly open, your radioactive materials are no longer secure. And if you decide that your security is going to be based on the entire building being locked up, then propping a single door open to, say, make it easier to move furniture or equipment in and out, means that every single lab and other storage location in your entire building has been compromised. The easier you make it for the people inside your building, the greater your potential problems if someone can gain access to your inner sanctum. For this reason, as RSO, I required that radioactive materials be stored in locked cabinets or refrigerators (or freezers) that were, themselves, behind locked doors. And, since security has to be enforced even after normal working hours, I even asked our Security officers to check posted labs whenever they were making their rounds – including nights, weekends, and holidays.

And then you get to “increased controls” (or “IC”) quantities of radioactive materials.

For a select group of radionuclides ( the Nuclear Regulatory Commission (NRC) has decided that a certain amount of radioactivity known as “Category 1” or “Category 2” requires additional precautions. These categories come from the International Atomic Energy Agency and they’re amounts of radioactivity that can pose a health risk to workers if the sources are lost or stolen – they can cause skin burns, radiation sickness, or other health effects if (say) the source is lost and then found by someone who doesn’t know they pose a risk. For Cs-137, for example, any source with more than 27 curies (Ci) of activity falls into Category 2 and must be protected; for Radium-226 the lower limit is 10.8 Ci, and for Cobalt-60 anything more than 8.1 Ci requires extra security measures. And here are what some of those measures might include.

  • Locks! You’ll need to include a combination of what’s known as engineered and administrative controls to restrict access to these sources. A locked door is an engineered control – a sign saying “Only Authorized Personnel Allowed” (and a corresponding list of those personnel, as well as a process for being added to that list) are administrative controls.
  • Background checks. You’ll need to get fingerprints and send them off to the FBI as well as running your own background check on anyone who will have unescorted access to high-activity sources. And, I should hasten to add, you don’t have to take the fingerprints or do the background check yourself – you’re allowed to ask your Security office or an outside organization to help out.

There’s more to security than this – quite a bit more. You should start by reading 10 CFR 37 and then maybe take a look at the IAEA document that started it all ( These will get you started.

Finally, and I can’t stress this enough – as you noted, you’re not a security expert. So you should work with people who are. Your local police precinct should be happy to pay you a visit and take a look at your security measures to give you advice; your institutional security office should be able to help you with background checks (as well as working with you on other security measures). The bottom line is that you’re not expected to know all of this yourself – find people to give you a hand when you’re out of your comfort zone.

And good luck!


  1. Source of the image used in this header is from The Georgetown University (GU) Radiation Safety Office website.