Montana regulators have approved the sale of Avista Corp. to a Canadian utility.

The Montana Public Service Commission voted Tuesday for Toronto-based Hydro One’s acquisition of Spokane-based Avista. Utilities commissions in states where Avista operates must approve the sale for it to go through.

The Regulatory Commission of Alaska approved the sale last week. Decisions are pending in Washington, Idaho and Oregon.

Avista is a co-owner of the Colstrip plant, a major eastern Montana economic driver that is under pressure to close from environmental groups and other states. The proposed sale could have implications for the coal-fired plant.

Avista and Hydro One set a 2027 end-of-life depreciation schedule for Colstrip’s two newer units, a date commissioners say is too soon and politically driven.