PITTSBURGH - A federal judge has rejected a Federal Trade Commission effort to block a deal by Equitable Resources Inc. to purchase Dominion Peoples and become the state's largest natural-gas utility.

U.S. District Judge Arthur Schwab yesterday granted Equitable's motion to dismiss a request for an injunction and temporary restraining order filed by the FTC in March, ruling that a state panel's approval of the intrastate deal is immune from federal oversight.

The Pennsylvania Public Utility Commission voted 4-0 in April to approve the acquisition, which includes a pledge by Pittsburgh-based Equitable not to request a base-rate increase in Pennsylvania before 2009.

The FTC said the deal would result in a monopoly in the Pittsburgh area that "may substantially lessen competition in the markets for local distribution of natural gas" to western-Pennsylvania customers.

Schwab said the action sought by the FTC would harm the PUC's ability to regulate such transactions.

The judge noted that the FTC complaint focused on about 500 commercial and industrial natural-gas customers who benefit from their ability to negotiate prices with both gas suppliers.