HARTFORD, Conn. — A rare October snow storm that caused record-breaking power outages could lead to increased electricity costs in Connecticut, where residents who endured days in the dark and cold already pay higher rates than any other state in the continental United States.

The price tag is expected to run to $100 million or more for the 12-day campaign that involved crews from as far as Colorado and Michigan in restoring power to more than 850,000 customers.

In a recent financial filing, the parent company of Connecticut’s main electric utility said it expects to recover costs for the Oct. 29 snow storm by going through regulators. With multiple investigations probing the utility’s storm response, however, the state’s energy commissioner and a key state lawmaker told The Associated Press that claims of mismanagement and subpar performance – if proven true – could block the company from passing costs on to ratepayers.

“We don’t know if it’s going to be borne by ratepayers. I think it’s very premature to make that statement,” said Connecticut state Rep. Vicki Nardello, D-Prospect, co-chairwoman of the legislature’s energy committee.

She said Connecticut Light & Power has insurance against storms and a reserve account, and state energy regulators can prevent the utility from passing storm-related expenses on to customers if they are deemed to be “imprudent.”

The rare, pre-Halloween nor’easter dumped up to 2 feet of wet, heavy snow that snapped tree limbs and power lines, and knocked out power to more than 3 million customers in the Northeast. It broke a state record for the number of customers left in the dark by a single storm that had been set only two months earlier when the remnants of Hurricane Irene slammed the Connecticut shoreline.

A week after the storm hit, 176,000 customers were still without power. Electricity was restored to virtually all customers by Thursday.