[Amps] BeO in tubes

[John Lyles]

Exactly, BeO is similar to asbestos in that it causes lung tissue damage (berylliosis - pardon for spelling) that can eventually develop into cancer. Although not in all cases. I know a guy (a ham) who machined it for years, and is always short of breath. Its a terrible thing. I believe that Eimac included that little red and white note in EVERY tube box, as it was probably simpler to do that than to try and get the proper notification into the proper tube carton in the shipping department. If they had not warned of the hazard, they could have been proven negligent in a lawsuit. Reading those notes, they always said something like "this tube MAY have BeO ceramic". 

There are pegmatite veins (called dikes) in the mountains near my QTH and one mine I have visited used to have meter long beryl crystals. In mid 1940s the miners extracted microlite, an ore of tantalum and niobium, from there. It was used for wartime work for electronic parts and tube elements (plates, getters). In the 1950s they extracted beryllium cyclosilicate ore. It was the leading beryl producer in North America in 1950-51, exceeding 13,000 kg per year. In 1958 the miner working the claim died, and production  ceased - over 690 tons of 11.2% BeO and 184 tons of 5.5% had been shipped from that one mine. Four miners dug and hauled the ore out. During the best days, they would bring about about a ton per day by hand. A mule named Beryl lived there and stayed in the mine for years. Needless to say, there were no dust masks or OSHA/MSHA safety regulations then. So most of them had that disease. 

A side note, Be was also used in neutron sources and neutron reflectors, and some of the early metal came from that same mine, for the Manhattin project, according to something I read. 


Sorry to digress from amplifiers! 
73
John 
K5PRO, northern New Mexico





Message: 2
> Date: Sun, 18 Nov 2007 08:51:39 +0000
> From: Steve Thompson <g8gsq at eltac.co.uk>
> Subject: Re: [Amps] Misconceptions about hazmat in ham radio equip
> To: amps at contesting.com
> Message-ID: <473FFD1B.80502 at eltac.co.uk>
> Content-Type: text/plain; charset=ISO-8859-1; format=flowed
> 
> John Lyles wrote:
> 
> > 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....
> 
> I'm intrigued by 'had to' - do you know why?
> 
> It is also in beryllium-copper metal used for EMI gasket material
> 
> As I understand it: Be metal in BeCu is very safe. Raw Be is 
> nasty, but no-one will encounter it in normal life. BeO is toxic 
> in the same was as asbestos - it's not poisonous, but the 
> particles cause chronic lung irritation that can develop into cancer.
> 
> Steve
>