The state has directed the council to decide by December whether to expand the city's landfill at Waimanalo Gulch or seek approval for a new dump elsewhere on the island.

Tam, who heads the council's Public Works Committee, said that while it's clear O'ahu will need its own landfill, officials should still consider other options. Shipping trash to the Mainland could be one of them, but it could also present major challenges, he said.

Federal and state environmental regulations could be big hurdles, and using a combination of ships and trucks could increase the chance of problems, Tam said.

"You would have to involve more parties, and that may make it open to more questions, and more possibilities of breakdowns," he said.

Still, officials should look at all possibilities for reducing the amount of trash going into a landfill on O'ahu, Tam said. The companies have been invited to present their proposals to the committee next Friday, he said.

Council Chairman Donovan Dela Cruz said he's also open to the idea of using a Mainland dump.

"I think it would be irresponsible if we didn't look at all proposals to minimize the use of landfills or hopefully eliminate the need for one," he said. "And we owe it to the taxpayers to look at every option to make a fiscally responsible decision."

Harris said he believes there are other motives at play.

"We all know you can't ship garbage off-island," he said earlier this week. "No one talks about it seriously. That's just put out there. Whenever a politician doesn't want to deal with a (not-in-my-backyard) issue, they sidestep it as an issue by saying it's going to be shipped to somebody else's community in some faraway, unknown place. The reality is we can't buy boat trips or airline tickets for our garbage."

The idea of shipping trash to the Mainland is not new. Councilman Mike Gabbard brought up the idea early this year, when the council was under pressure to make a decision on an O'ahu landfill by June. The state Land Use Commission later extended the deadline to December.

Gabbard and Councilman Gary Okino have visited a landfill in Washington state, and both said they were impressed with the operation.

"They showed me their railway system, their unloading area, and the characteristics of the landfill," Okino said. "It was pretty impressive, actually."

The plan would involve shredding garbage and compressing it into blocks encased in shrink-wrap, then loading it on ships at Sand Island, Okino said.

City environmental services director Frank Doyle said a Seattle company, Pacific Rim Environmental Resources, gave the city an unsolicited proposal for shipping garbage to the Washington site. He said he was reviewing the proposal and could not divulge details.

Another company, Idaho Waste Systems, has proposed shipping trash to Idaho or Oregon, and has invited up to three council members to tour its facilities, Dela Cruz said.

Doyle said Idaho Waste Systems has talked with city officials but has not submitted a detailed proposal.

"All I do is listen," Doyle said. "They've both been speaking to a lot of people."

Neither company could be reached for comment yesterday.

Doyle said he has "serious reservations" about trying to ship trash to the Mainland.

Ensuring that Hawai'i fruit flies aren't transported to the Mainland with garbage is one problem, and cost could be another, he said. Such a plan could also compete with the city's efforts to start islandwide residential recycling and could make O'ahu dangerously reliant on a process that could be difficult to continue indefinitely, he said.

"It's all well and good to say we're going to ship garbage out, but I'm not sure that's the best thing to do from a sustainability point of view," Doyle said.