The Federal Energy Regulatory Commission has decided not to allow Columbia Gas Transmission Corp, to charge customers for $2 million of costs incurred during the winter of 1977.

The commission said Columbia Gas wrongly failed to curtail gas deliveries to industrial boilers in October 1976, thereby unnecessarily incurring the $2 million cost of emergency gas purchases later that winter.

Columbia Gas is an interstate pipeline which transports natural gas to West Virginia, Kentucky, Maryland, New Jersey, Virginia, New York, Pennsylvania and Ohio.

A spokeswoman said the commission voted Thursday not to allow Columbia to pass that extra cost on to its customers. It was not immediately clear whether this would require refunds or, instead, reduce customers' gas bills in the future.

The decision becomes legally binding only when it is formally issued by the commission, a move which normally follows the commission's vote within a few days.

The action was prompted by Sen. Howard Metzenbaum, D-Ohio, whose state was among those most heavily hit by gas shortages during the severe winter of 1976-1977.

Metzenbaum wrote to the commission alleging that Clumbia Gas drew upon its stored natural gas supply too heavily in the autumn of 1976 and, as a result, ran short of gas during the winter when it had to purchase high-cost emergency supplies.

A commission administrative law judge, Samuel Kanell, issued an intial decision last February, disapproving the recovery by Columbia Gas from its customers of some $2 million for those emergency purchases.

The commission agreed, finding that Columbia Gas should have acted in the last week of October 1976, to prevent further withdrawals of natural gas for boiler fuel.

Yesterday Columbia Gas said the commission's decision only basically affirmed last Febraury's action by Judge Canell. The company also pointed out that the judge found that Columbia Gas, by and large, acted properly in managing its gas supply during the period in question. The judge also "essentially found the positions taken" by Metzenbaum and the commission staff "were without merit," Columbia Gas said.