Addendum: hard to believe his search didn't yield anything but damn fine reason to gather some facts and post them for FL users...
Most common transformer contamination these days is from units drained and flushed years ago still carrying trace contamination (5-500ppm). PCBs are readily absorbed through the skin so zero-tolerance is implied. One touch of this persistant organic pollutant will put measureable quanities into your tissues.
http://www.rachel.org/bulletin/index.cfm?issue_ID=802
Most common exposure source is small oil capacitors from old TV's, refrigerators and Fluorescent lamp ballasts. Anything pre-1979 is suspect and should be treated like poison.
"EPA banned the manufacture of PCBs in 1978, PCBs were commonly incorporated in the manufacture of fluorescent light ballasts. The use of PCBs in ballasts manufactured prior to 1978 is not regulated by EPA. All light ballasts manufactured since 1978 which do not contain PCBs should be marked by the manufacturer with the statement, ANo PCBs.@ For those manufactured prior to that time, or for those ballasts which contain no statement regarding PCB content, you should assume that they do contain PCBs."
"If the ballast does contain PCBs, they are located inside the small capacitor. There would be approximately 1 to 1½ ounces of PCBs in the capacitor itself. If the ballast fails, the capacitor may break open, allowing the PCBs to contaminate the surrounding tar-like material and drip out of the fixture. The capacitor does not always leak when the ballast fails, but when it does, measurers should be taken to limit or avoid personal exposure."
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