Answer to Question #13924 Submitted to "Ask the Experts"

I have collected compasses for five years. I have 16 with radium dials. All glass is intact. I keep them in my living room in a glass cabinet. Am I safe?

It sounds as though you've got a cool collection! I can give you some general guidance but, without knowing more about each of the compasses it's hard to give precise information. So, here goes.

With radium dials, the radium is found in the paint that was used to make the hands and tick marks luminous. And that raises two different concerns—contamination and radiation.

The contamination would come from the paint. Over time the paint can become powdery or can flake off, contaminating the dial and everything beneath the glass cover. Normally, the cover will contain the contamination as long as it's tightly sealed, but if the glass cracks or the seal is broken then the contamination can spread to your cabinet. I saw this happen with a number of compasses that we found in a dumpster in New York City when I was working for the city's health department. The dumpster set off some radiation alarms and we responded to see what was happening. The compasses were beautiful Army models from the 1940s or 1950s. My colleague and I both wanted to grab one for our own collections of radioactive products. However, we noticed that the glass cover was cracked, we did a smear wipe and found the outsides were contaminated. So we sealed them up in a double-locked bag and moved them to storage until we could arrange disposal. This incident illustrates why you need to be aware of the potential for contamination! As a radiation guy, I have a number of radiation detectors at home that allow me to do a quick contamination survey every now and again, just to be safe. My guess would be that you don't have a Geiger-Mueller (GM) "pancake" detector, but you might be able to borrow one (see below).

The radiation comes from the radium in the paint. Radium gives off both alpha and gamma radiation. The alpha radiation is what interacts with the paint to give off light; the gamma radiation is what can escape your cabinet to give exposure. Having said that, it's almost certainly not enough radiation to hurt you, and just because it might be measurable on a radiation detector does not mean that it's harmful. This is where I can't do much more than guess because the amount of radium in the paint and the amount of paint on each compass is what will determine the radiation dose rate. Again, it's not likely to be harmful, but you should be aware that it's there.

What you might want to do is to go to the Health Physics Society's web page to see if you can find your local HPS chapter. See if you can make contact with someone at the chapter to find out if there's someone who might be interested in paying you a visit to do a radiation and contamination survey. If any of the compasses are leaking, they might also be able to advise you one the best way to handle it.

Alternately, see if there's a research university or a nearby hospital with a nuclear medicine or radiation oncology department in your area, either of these will likely have a radiation safety office (RSO) (maybe as part of environmental health and safety department). If you contact them, they might be interested in measuring the compasses for radiation and contamination or they might be willing to lend you an instrument for a day or so. When I was a university and hospital RSO we had people contact us from time to time with questions about this sort of thing. As long as the person calling didn't sound nutty and was willing to bring their things to our office we were usually willing to help out. We never found anything that was even remotely dangerous, nor did we when I worked for the State of Ohio in the 1990s.

The bottom line is that your compasses are very unlikely to pose a health risk to you and your family and/or pets. But, it's still not a bad idea to check for contamination and radiation. That's in keeping with the central philosophy of radiation safety, keeping everybody's exposures As Low As Reasonably Achievable (ALARA).

P. Andrew Karam, PHD, CHP