TORONTO - Ontario's Progressive Conservatives are demanding the CEO of Hydro One be fired because of "outrageous" over-billing and poor customer service at the government-owned utility.

London-area Tory Jeff Yurek says a family-run grain elevator that usually pays at most $4,500 a month for electricity got a three-month bill from Hydro One for $233,693.

Yurek calls it the worst example so far of seemingly unexplainable Hydro One bills that constituents call in every day to complain about, and says it shows the giant utility cannot get a handle on its billing problems.

Ontario's ombudsman has launched a formal investigation into Hydro One's billing practices after his own investigators "got the runaround" and experienced "stonewalling" from the utility.

Yurek says Hydro One CEO Carmine Marcello allowed a culture of lousy customer service to fester throughout the utility that won't change until the man at the top is replaced.

He also says appointing former Liberal cabinet minister Sandra Pupatello to chair the Hydro One board won't change anything because she was part of the government that approved the new billing system, smart meters and the green energy act.