Environmental problems at O'ahu's main garbage dump "could cause a crisis of disastrous proportions," according to Joseph Hernandez, a former dump manager.

Gary Siu, a state environmental engineer who prepared the Waimanalo Gulch Sanitary Landfill's operating permit, is backing up the assertions and calling for a thorough cleanup there.

But both have come under fire, however, as the state investigates whether Hernandez improperly paid for outings that included Siu.

They and environmental activist Carroll Cox are suing state Health Director Dr. Chiyome Fukino in U.S. District Court over alleged secrecy in negotiations over a $2.8 million state fine against the dump for numerous health and environmental violations.

Larry Lau, state deputy environmental health director, would not discuss specific allegations while the lawsuit is pending.

But the Health Department continues to monitor and inspect the site, Lau said.

"If we think there's an imminent and significant hazard, we'll take appropriate action," he said.

Excessive heat is one big concern at the dump, according to Hernandez, who oversaw operations there until 2005 as district manager for Waste Management of Hawai'i, the company that runs the site.

The dump's smoldering garbage is not supposed to exceed 130 degrees Fahrenheit, "but I have been informed by (Department of Health) representatives that they have found temperatures exceeding 170 degrees," Hernandez said in court papers that include his first public statements about the suit and the dump's problems.

Waste Management did not directly deny that allegation but said the site is under control.

"We think that it is irresponsible for a former employee who was terminated nearly two years ago to comment on the current conditions of the landfill," said company spokeswoman Kit Cole. "The current management team at the landfill has significantly improved operations to ensure that the landfill is safe and environmentally sound."

The company is working closely with all regulatory agencies "to determine what, if any, action is necessary," Cole said.

Hernandez and the other plaintiffs are seeking court orders that would allow them to participate in negotiations over the fine and preclude the state from settling for a lesser payment while the suit is pending. Cox said he fears problems would be covered up if the fine is negotiated in private.

Public participation is required by the federal Clean Water Act, Solid Waste Disposal Act and Resource Conservation and Recovery Act, the suit charges.

The Health Department fined the dump one year ago after documenting dozens of environmental violations there. The site, near Kahe Point on the Leeward Coast, is owned by the City and County of Honolulu, which has joined operator Waste Management in contesting the fine.

Hernandez said in a sworn declaration that he had tried to raise environmental standards at the dump to address neighbors' complaints about foul odors and windblown trash.

"Despite these concerns, I was forced to work with current resources and assets that were insufficient and ineffective in operating the landfill," Hernandez said in the document.

Siu and Hernandez had reached an agreement that would have modified the dump's permit by requiring Waste Management to improve its operation, but the Health Department rejected the changes, according to Siu.

The dump "is in an unpredictable state based on the abnormal gas and temperature conditions, which can affect public health and the environment," Siu said in court papers.

"As a member of the community, I am demanding that the Department of Health not only impose a fine on the owners and operators of the landfill, but also require that they immediately remedy the problems and violations at the landfill before issuing a new permit," Siu said in a declaration.

In the meantime, the state attorney general's office is investigating whether Hernandez improperly "spent money on" Siu at restaurants, a golf club or other outings.

Waste Management raised the spending allegations during private talks with state officials over the fine, state records show.

Neither Hernandez nor Siu has been charged with wrongdoing, and their attorney has characterized the allegations as an attempt to scapegoat them for the dump's problems. They filed suit shortly after the allegations surfaced.

State Senate President Colleen Hanabusa also has petitioned the state to become a party to the settlement talks but is not a party to the suit.

The dump's permit for accepting municipal solid waste expires in mid-2008. The city is seeking permission to expand the facility and operate it for at least 15 more years.

Public and private trash haulers dump about 1,400 tons of garbage and incinerator ash at the landfill per day.

Reach Johnny Brannon at jbrannon@honoluluadvertiser.com.