Depot personnel worked until 11 p.m. Thursday to clean up spilled oil containing toxic polychlorinated biphen-yls, or PCBs.

Either lightning or a short circuit damaged a wooden power pole that caused a transformer in TAD's maintenance area to fall about 1:30 p.m., spilling about 16 gallons of oil onto the dirt, said Susan Broadbent, acting depot public affairs officer. Tests showed the oil contained PCBs.No people were exposed to the carcinogenic substances, she said.

Broad-bent said the depot's fire and security departments contained the spill, placed the hazardous material in sealed drums and transported them to an approved toxic substance control storage facility.