[Amps] Misconceptions about hazmat in ham radio equip

[John Lyles]

PCB was/is a good insulating oil, in that it was least flammable. The replacement oils now are more flammable. In capacitors, and transformers. I have seen numberous GE 4 uF 45 kV capacitors rupture and spit flames at work about 5 years ago, when they were at end of life. These were in pulsed power energy storage application. They used either Geconal or Dielektrol, GEs own names for their oils. Succcessively later vintage oils burn even easier. Some high power oil-filled capacitors are now using a mixture containing rape seed oil (canola) which is also flammable. 

PCB is not good to drink or bathe in, but documented accounts of harm from it, were from laboratory rat experiments. If you take in sufficient dose of any of the transformer oils, you can get all sorts of effects. I know technicians who developed sensitivity to Diala, Shell's transformer oil used in many substation-sized units. Heating the oil, such as in use, causes volatile materials to vaporize and are easily injested when you breathe.

Diala also has a pungent almost disgusting odor, like PCB and some others. So the test for pungent or stinging vapor isn't enough to ID PCB oil. I happen to like the smell myself, but I wouldn't sit in it for long. 


Now for beryllia. It is used in SOME power tubes, not LOTS of them. Eimac had to include a disclaimer about it with every tube, although most air-cooled and water-cooled tubes use alumina, not beryllia. It is also in beryllium-copper metal used for EMI gasket material in some many things. Also in the bottom insulating material under some high power RF transistors. (not the top white cap but underneath the device). But to injest it, you have to grind up or cut and breathe the dust. Again, exposure of one time is not horrible, but repeated exposure, such as doing this for a job, like a mechanic working on automotive brakes all his career, is unhealthy. 


It would be reasonable to say that many billions of dollars have been wasted world-wide freaking out about PCB or that ceramic material, whereas the danger of HV, of getting scaled by too hot water, by automobile accidents, is much more heinous. However, keeping things in context to ham radio, its best not to drink PCB oil or cut up and grind BeO2 into dust and breathe this. Incidental usage of these materials in amplifiers, however, is NOT harmful to humans. Over-regulation have pushed these materials as safety/environmental concerns in business world. The companies who remediate and remove them are making plenty of money now. 

John 
K5PRO