An environmental activist and two men who figure in an investigation by the attorney general's office sued the state Health Department's director in federal court yesterday over alleged secrecy surrounding problems at O'ahu's main garbage dump.

The suit charges that Dr. Chiyome Fukino is improperly excluding the public from negotiations to settle a $2.8 million fine her department levied against the Waimanalo Gulch Sanitary Landfill last year for dozens of environmental violations.

The fine is being contested by the city, which owns the Leeward Coast site, and Waste Management of Hawai'i, which operates the dump there.

The suit seeks a court order that allows the plaintiffs to participate in the settlement talks.

One of them, environmental activist Carroll Cox, said he fears improper handling of asbestos and other health hazards at the dump will otherwise be covered up.

"We're truly concerned that they've gotten away from protecting public health and are now protecting the big boys who run the landfill," he said. "We're hoping the federal court orders this process opened up. It's not asking much."

The suit was filed yesterday in U.S. District Court. Fukino had not seen the suit by late afternoon and had no immediate comment, a spokeswoman said.

The attorney general's office has been investigating whether a former dump manager "improperly spent money" on a health department official who dealt with the site.

The two, who are also plaintiffs in the suit, have not been charged with wrongdoing. Joseph Hernandez was a manager at the landfill until 2005, and Gary Siu is a Health Department environmental engineer who was involved in issuing permits for its operation, according to attorney Michael Ostendorp.

"The plaintiffs have concerns that the Department of Health, the City and County of Honolulu, and Waste Management will settle (the fine) for something that's less than sending them a message to not do it again," he said.

Ostendorp said he will seek a court injunction next week to preclude a settlement while the suit is pending.

Reach Johnny Brannon at jbrannon@honoluluadvertiser.com.