The cost of permanently closing a long-defunct city landfill in Waipahu has more than doubled while officials wrangle over how to deal with any lingering environmental problems.

About $7 million had been set aside for the work, but it now is expected to cost an additional $10 million, according to city environmental services director Eric Takamura.

The 49-acre site, on Waipi'o Peninsula beside Pearl Harbor's West Loch, was used as a dump from the early 1960s until late 1991.

The city later built a soccer complex nearby, and is considering opening up the landfill site for recreational use after environmental work is completed.

About 2 million cubic yards of garbage and incinerator ash are buried in the landfill, city records show.

Part of the site is leased from the Navy, which has yet to approve the city's plan to permanently cap the landfill and monitor conditions, officials told a City Council panel Thursday.

"We can't get the Navy to agree," said Wilma Namumnart, assistant chief of the city's refuse division.

In the meantime, the estimated cost of the work has skyrocketed.

Navy officials involved in the dispute could not immediately be reached for comment.

The 12,600-acre Pearl Harbor Naval Complex, which includes the landfill property, is a federal "superfund" site, and that triggers environmental regulations and oversight that would not otherwise apply to the landfill closure.

Among the work needed at the landfill is the removal of ash from the Pearl Harbor shoreline and grading to improve drainage to allow for recreational activity in the future, according to a 2004 environmental report commissioned by the city.

The site also must be capped with a barrier, such as a synthetic geomembrane, and layers of dirt to prevent anyone from being exposed to garbage or ash, the report says.

"The main thing is to cover it and make sure the material stays in place, and that in future use no one breaks the cover," said Steven Chang, solid and harzardous waste chief for the state Health Department.

The site also would have to be monitored for methane gas emissions and groundwater contamination, according to the city's report.

The landfill and surrounding area have drawn considerable scrutiny since illegal dumping was discovered nearby in 2003, at the site of the old Waipahu incinerator.

The state Health Department fined the city $542,459 after removing more than 30 tons of compacted washers, dryers, propane tanks, stoves and other junk from the incinerator site, which is adjacent to the landfill. Bricks from the demolished incinerator were also illegally dumped in the closed landfill, health officials found.

A former city refuse facility superintendent later pleaded guilty to 24 misdemeanor charges in connection with the illegal dumping.

CITY PLAN DELAYED

Meanwhile, officials said Thursday that a long-awaited comprehensive city plan for managing O'ahu's garbage will be delayed until October.

Council chairwoman Barbara Marshall noted that the plan had first been expected last December and said she was getting fed up with repeated delays.

"I don't see the excuse for it, frankly," she said.

Martin Okabe, Takamura's assistant at the city's environmental services department, said officials are trying to make the $800,000 report as comprehensive as possible.

But he could not explain why the city had not yet formed a solid waste advisory committee that must review the plan, even though he knew of that requirement since December.

"I can't answer that right now," he told Marshall.

City refuse assistant chief Namumnart said the city has no contingency plan in case the state Land Use Commission rejects its request to expand the Waimanalo Gulch landfill on the Leeward Coast, where most of O'ahu's trash and incinerator ash is now dumped.

That landfill's operating permit expires next year, but the city hopes to keep the site opened for at least 15 more years.

"I'm an optimist," Namumnart said of the pending state approval.

CITY OPPOSES SHIPPING

Takamura said a key reason the city opposes offers by private firms to ship trash to a Mainland dump is that such an arrangement would leave the city without control of its waste stream.

That would invalidate a pending request for proposals to expand the H-Power garbage-to-energy plant or build a new facility that uses different waste disposal technology, he said.

The city is entering negotiations to buy the H-Power plant, which incinerates trash to turn a turbine that generates electricity.

Expanding the 17-year-old plant or building an improved version would be the city's best long-term solution to garbage disposal, Takamura said.

H-Power is owned by a bank and investors, and should cost less than $100 million, he said. A new plant could cost up to $400 million, he said.

Reach Johnny Brannon at jbrannon@honoluluadvertiser.com.