Copper thieves forced the closure of seven businesses after dismantling a Dundee substation.
Workers from Scottish Hydro Electric scrambled to repair the damage caused after the company’s substation at the Wester Gourdie Industrial Estate was broken into.
Police are investigating the raid, which also triggered an oil leak into drains, causing a serious environmental issue.
A spokeswoman for Scottish Hydro said the theft was “extremely dangerous”.
“Thieves came through overnight on Tuesday, cut the padlock and switched off the substation,” she said.
“They then proceeded to drain the oil there, before extracting the copper wiring.”
Seven units in the industrial park were left without power throughout Wednesday, causing scores of workers at the Johnson Matthey battery factory and other premises to be sent home.
But according to Scottish Hydro, whose engineers worked through yesterday to rebuild its substation, there was also a major environmental impact.
“The oil they tipped over has now gone into an area drain, creating a potential health risk,” the spokeswoman said.
“We’ve now had to liaise with the Scottish Environment Protection Agency, and an entire investigation will need to be launched as to the impact this may have on the environment and people in the area.”
The company’s spokeswoman added that the repairs required were “extensive”.
“The entire inner workings of this substation were dismantled,” she said.
“I can’t emphasise enough how very, very, very dangerous this theft was.
“These people were breaking into our substation on the presumption it was off or that they at least knew how to shut it off without knowing how our operating infrastructure is set up.”
A spokesman for Police Scotland’s Tayside Division said: “A theft was reported to us at 8.26am on Wednesday after the crime occurred overnight. Inquiries are continuing.”
Rebecca Trengove, of Johnson Matthey, said workers at the factory would be playing catch-up today to fill orders.