Two of the companies that want to ship some of O'ahu's trash to a Mainland landfill have filed a protest challenging a third company's bid, forcing a delay of the contract process.

Off-Island Transfer, which bid $204.21 per ton to ship the trash, and Simcoe Environmental Services Inc., which said it would charge $184.47 per ton, allege the low bidder, Hawaiian Waste Systems, is "under valuing" the project by bidding $99 a ton to do the work.

Both companies filed separate complaints with the city office of Budget and Fiscal Services and by law the bid review process cannot be completed until the protests are addressed.

"Currently, the protests are being evaluated, and pursuant to state law, a stay is in effect and no further action on the solicitation or award of a contract can be taken until the protests are resolved," said Eric S. Takamura, director of the city Department of Environmental Services.

Attempts to reach the three bidders were unsuccessful yesterday.

The bids were unsealed in June and a contract was scheduled to be awarded sometime this month.

Department officials declined to comment about the specifics of the protests, which could threaten the city's stated goal of starting the project by July 1, 2009.

City Council member Gary H. Okino said he was aware of the challenges but did not know the details. He said he hopes the protests do not derail the plan.

"We need to proceed. It's part of the whole (waste management) scheme," Okino said. "If we don't have it, that's just more stuff that's got to go into the landfill."

The three-year contract, with an option for two additional years, requires the winning bidder to ship 2,050 tons of trash per week and up to 100,000 tons a year to a Mainland landfill.

It costs less than $30 per ton to dump municipal solid waste into the Waimanalo Gulch Landfill.

The amount that would be shipped is less than 6 percent of the total 1.76 million tons of solid waste O'ahu generates annually, but proponents say it's one of several alternatives that will slow the closure of the island's main landfill and allow for the expansion of waste-to-energy technology.

If the contractor ships more than 100,000 tons in a given year, it will be paid 90 percent of the costs it incurs to ship the trash.