If Honolulu's main garbage dump is forced to stop accepting trash when its operating permit expires in May, Mayor Mufi Hannemann will ask Gov. Linda Lingle to declare a state of emergency to keep the site open, the city's top environmental official said yesterday.

The city will not operate the Waimanalo Gulch Sanitary Landfill illegally if the permit is not extended, environmental services director Eric Takamura said in testimony before the Honolulu Planning Commission.

The only other landfill on O'ahu that could be quickly pressed into service in an emergency is a privately owned construction debris facility in Nanakuli, and that's not an option for Hannemann because Leeward Coast residents have strongly objected to dumping trash there, Takamura said.

It's not yet clear whether the situation will lead to a standoff between the mayor and governor, but Takamura's statements indicate O'ahu could be in for a nasty political trash battle.

Lingle's spokesperson could not be reached late yesterday.

Hannemann wants to extend the current Waimanalo Gulch permit for at least two years and is planning a 60-acre expansion that could keep the controversial site open 15 years longer.

Takamura was the first witness called in a hearing sought by state Senate President Colleen Hanabusa and the nearby Ko Olina Resort and Marina, which want to block the extension and force the landfill's closure.

Takamura said it would likely take at least five years to plan, construct and secure permits for a new landfill if a suitable site were immediately made available. The city reviewed alternative locations but decided in 2005 that none was feasible, he said.

Hanabusa, who lives at the resort and represents the Leeward Coast, has pushed for the city to ship trash to a Mainland dump if it can't be disposed of here.

Takamura said that might be an option but could be prohibitively expensive.

"Anything's possible, but at what price? That's the question," he said during the packed hearing at Kapolei Hale.

Three companies have been working to set up trash-shipping operations here, but none is ready to begin yet, and the city has yet to offer a contract or give up its control of the island's trash flow.

A Seattle company, Hawaiian Waste Systems, has indicated it could begin shipping at least 100,000 tons per year in about six months, at rates comparable to those the city charges garbage haulers now.

The island generates much more trash than that — more than one million tons of trash per year. Roughly half is burned at the H-Power garbage-to-energy plant.

About 200,000 tons of ash and residue from the plant is dumped in a special section of Waimanalo Gulch each year, so shutting the site down could disrupt H-Power operations, Takamura said.

Since 2004, ash has been piled higher at the dump than a state Health Department permit allows. The city is asking that the height limit by increased by 40 feet.

Takamura could not say how a rejection of the request would impact the amount of space left for trash.

The height limit was lowered in 2001 after officials discovered that a liner around several garbage cells was made of an inferior material that could weaken the hillside dump, former Waimanalo Gulch manager Paul Burns testified.

"It is not quite as resistant to movement," Burns said of the material. "But the landfill is stable. There never was any sense that the landfill was going to slide."

A large "toe berm" that wasn't originally planned for the site was also constructed near the lowest end of the gulch to act like a retaining wall and strengthen the landfill, Burns said.

The city won approval for an earlier expansion of Waimanalo Gulch after promising to close the site next year. The City Council considered alternatives in 2004 but decided that space mauka of the current dump should become the new one.

More than 20 additional witnesses have been called to testify before the Planning Commission makes a decision.

If the panel approves the two-year extension, it would still require separate permission from the state Land Use Commission. The 15-year expansion would also require approvals from both commissions.

Reach Johnny Brannon at jbrannon@honoluluadvertiser.com.