The letters, from state Rep. Ralph Samuels were sent to companies that now own gas transmission companies that were partners in the Alaskan Northwest National Gas Transmission Co, or ANGHTC, in the 1980s.

The companies included MidAmerican Energy Holding Co., which formerly owned Northern Arctic Gas Co.; Sempra Energy, former owner of Pacific Interstate Transmission Co.; PG&E Corp., former owner of Calaska Energy Co.; NiSource Inc., former owner of Columbia Gas Transmission Corp.; Loews Corp., which formerly owned Texas Gas Transmission Corp.; and the Williams Cos., former owner of Northwest Alaskan Pipeline Co.

“Would you be willing to waive your rights under the ANNGTC partnership agreement? Do you believe the corporate structure used by TransCanada in its Alaska Gasline Inducement Act application violates any obligation to your company?” Samuels asked each of the companies.

TransCanada says the former partners, which withdrew from the consortium between 1981 and 1994, have no claims against it or a new subsidiary formed to do the Alaska gas project. Company vice president Tony Palmer told legislators in hearings last week that the former partners are entitled to payment of capital invested in the consortium, plus interest, only if the consortium builds the project. Palmer said TransCanada has formed a new company, TransCanada Alaska LLC, to do the project.

Two of the companies have expressed interest in being part of an Alaska gas project, however. MidAmerican submitted a proposal to develop an Alaska pipeline in 2005 but then withdrew, and considered submitting a bid in the state’s latest solicitation for proposals.

Sempra also has been interested in an Alaska LNG project, and at one point formed an alliance with an Alaska municipal group working on LNG, the Alaska Gasline Port Authority. Sempra withdrew when it became apparent that the Alaska state government favored an all-land pipeline project.

The potential liability against TransCanada, which totals $9 billion with accumulated interest, has emerged as an issue in Alaska over concerns that a potential cloud on the project could impede TransCanada’s ability to attract partners. Palmer has assured legislators that even if claims were valid they would not be allowed to be part of the capital base for the project in terms of calculating the tariff for transporting gas.