Bushwick PS 45 In Brooklyn - Lighting Ballasts W. 600K/Million Parts PCB (Legal Limit 50) - NYT

The federal Environmental Protection Agency has found the highest levels of leaking PCBs to date in its inspections of New York City schools, at Public School 45 in Bushwick, Brooklyn.

Agency officials said that an inspection of lighting ballasts at the school on Feb. 12 revealed PCB levels of up to 660,000 parts per million, far beyond the regulatory limit of 50 parts per million.

Previous inspections at five other school buildings since January had found levels of up to 260,000 parts per million.

The likely cause was that capacitors in many of the lighting fixtures had “burned out and completely failed,” officials said. “This allowed the PCB-containing oil to seep through the potting material in almost pure form,” the agency said in a statement. “In most of the fixtures tested in this school the actual casing around the ballasts had also broken, allowing the high concentration of PCBs to contaminate the surface of the ballasts, the fixture housings, the wires and the diffusers that cover the lighting fixture.”

EDIT

http://green.blogs.nytimes.com/2011/02/22/striking-pcb-levels-found-at-new-york-school/

That black/brown shit slowly seeping down and staining the fixtures...
That's what they're talking about. It's the contents of a load ballast resistor.
Pretty common in most fluorescent fixtures. Basically just PCBs dissolved in oil/tar.

I'm sure you've smelled it at one point or another when a ballast critically fails. Fills the who room with an elctronic & burnt rubber/plastic smell. MMMmmmm.