Most of my collecting activities are aviation related, but I guess this thread could apply to any health and safety issues applying to militaria in general.
Among other things, I collect aircraft gauges and instruments. There has always been a lot of discussion about radioactivity issues with gauges, clocks and watches etc.,due to the use of luminescent radium based paint on the dial faces, used in the 1960's and years previous.
For that reason, I don't buy gauges that have cracked glass faces or other damage which might allow radioactive emissions. In the past, I've tested some by placing the dosimeter directly on the face of the gauge, and have always got a reading roughly equal to normal background readings.
A couple of points worth noting are that all the gauges I've tested are in well sealed, good condition, or unissued mint condition. The other point is that the background levels in Europe, the UK, USA etc. are two to three times higher than here in Australia.
I've read advice recommending that gauges be displayed not as a large group, to avoid a combined elevated reading. So I decided to test a group of eight - a mixture of MiG gauges, B-17, B-24, F100 Super Sabre etc.. The measurement was done in microsieverts, with the sievert being the measurement that evaluates the effect on living material.
Anyway, the geiger counter got a little bit hyperactive when held close to the group, so I immediately suspected there might be a culprit among them. Indivual testing soon tracked it down to a U.S. manufactured oxygen flow indicator, the 'Blinker' commonly found on B-17's, C-47's P-51's etc..
At a distance of 2.5 metres - o.1 microseiverts ( same as the normal background reading in this area)
closer readings were;
0.12 at 1.5 metres
0.18 at 1.25m
0.26 at 1m
0.32 at 0.75m
0.51 at 0.35m
1.06 at 0.25m (10 x background reading)
and here's the clanger -
44.0 microseiverts directly at the gauge face (440 times the hourly dosage rate of background radiation).
To put it into perspective, holding the gauge in your hand for one hour gives about the same dose you would normally get from eighteen days of normal living.
This gauge is well sealed and in unissued, unused condition, so there's no obvious leakage points.
As I understand it, radium is Alpha based which is easily stopped by the glass. When the luminescent paint breaks down, it gives off by-product Beta and Gamma particles, which can be a concern if the glass face is cracked or broken. If the glass is removed or broken, the radioactive paint dust containig Beta/Gamma particles can be absorbed into the skin or ingested.
This gauge is emmitting a huge amount more than the small amount of radium paint would be capable of, so I'm a bit suspicious that it might have some other component emitting Beta particles.
There's no other explanation as to why so much is coming out of a well sealed instrument.
I'll put up a post on an aircraft restoration forum and see if anyone has a bit more information on these gauges.
Here's my observations and some tips:
If each individual gauge reads normally, then a lager group doesn't seem to have any significant elevated reading as a group.
If you collect gauges, spend $100 on ebay and get a dosimeter. Test every gauge that you buy.
If you get elevated readings, don't display gauges where you are likely to be in close contact for extended periods (eg. on a shelf beside the computer where you spend a lot of time.).
Get advice before opening up old gauges for restoration. In Canada for instance, it's illegal to open up or interfere with any radioactive luminous device without a permit from the nuclear safety authorities.
Think twice before buying gauges with broken glass faces.
Has anyone else got any scary collecting stories. I'm sure there would be the obvious ones - explosives, chemicals etc..