what they don't want is transformer getting into drinking water, the problem is usually that it leak, PCB go into environment through storm drain.
Personal exposure is of course no joke either.
Usually big power companies have a special lab for testing stuff rapidly, if its in a "old " city
The problem is it accumulates. You find it in wild life that is exposed and its kinda linked to cancer clusters and such (of statistical significance)
Its the same story every time, there is always some group that gets really lucky.. like those 90 year old asbestos workers that still smoke cigar.
Point is, its a proven carcinogen. But I think so is gasoline (which you can get away from now thankfully)
Some new dirt on PCB might come from missile silos. apparently the missileers are not very healthy after working their jobs.. some say its PCB related.
But I think if you don't get it in your water, and its a 1 time exposure... your probobly gonna be OK. But if you have concerns their entirely justified
JUst don't be a dick, get someone to take it to a proper disposal when you gotta get rid of it