The state Department of Transportation would be required to conduct an environmental study on the impact of the Hawai'i Superferry on state harbors, under a measure approved by the state Senate yesterday and moved to the state House.

Prospects for the bill in the House are doubtful.

The vote was among a handful to complete bills by yesterday's deadline for crossover between the chambers. The House voted to send the Senate a bill extending state and county employee health coverage to gay couples and others who register as partners.

Crossover is the first big deadline of the 60-day session.

Senators agreed to the environmental impact statement for Superferry only after amendments that require the state to pay for the review and make clear that it would not stop the scheduled July launch of service.

State Sen. J. Kalani English, D-6th (E. Maui, Moloka'i, Lana'i), said the review would focus on the impact on state harbors and would not concentrate solely on Superferry. "We have to change our thinking on this. It's no longer a Superferry bill, it's an EIS bill for our harbors."

But state Senate Majority Leader Gary Hooser, D-7th (Kaua'i, Ni'ihau), said the bill is clearly aimed at Superferry. "We have a responsibility to our constituents to look into this," he said.

The bill extending health benefits for gay couples and other partners grew out of the failure of civil-union legislation. It would expand the state Employer-Union Health Benefits Trust Fund to recognize those who register as reciprocal beneficiaries.

State law grants people who register many of the same rights as married couples. The option is available to gay couples, siblings or anyone else who by law is unable to marry, although it's rarely invoked in practice.

Some gay activists opposed the health benefits bill as a sidestep that would drain momentum from fuller same-sex rights, but it received plenty of support in the House.

"I think it's a good civil rights bill. I think it's a good bill for everybody," said Rep. Kymberly Pine, R-43rd ('Ewa Beach, Iroquois Point, Pu'uloa).

Reach Derrick DePledge at ddepledge@honoluluadvertiser.com.