OLYMPIA, Wash. -

Washington voters are narrowly approving gay marriage in the state, following the lead of voters in Maryland and Maine, where ballot measures on same-sex unions also are holding slim leads.

With about half of the expected vote counted Tuesday night, Referendum 74 was passing with 53 percent of the vote.

The referendum asked voters to approve or reject the state's new law legalizing same-sex marriage. That law was passed by the Legislature and signed by Gov. Chris Gregoire earlier this year, but it's been on hold pending the election's outcome.

About $13.6 million was spent on Washington state's campaign, with the bulk of it coming from gay marriage supporters.