$50-Million Claim Filed Over Waste-Dump Site : Environment: Rolling Hills Estates residents allege that the county sanitation districts improperly dumped toxic materials at old landfill.

A group of Rolling Hills Estates residents who live near an old waste dump filed a $50-million claim against the Los Angeles County Sanitation Districts Thursday, alleging the agency improperly filled the site with hazardous or toxic materials.

The claim alleged that the sanitation agency was supposed to fill the developable portion of the Hawthorne Canyon landfill with compacted earth but, in addition to toxic substances, filled the site with municipal waste.

John Gulledge, a solid-waste management expert for the sanitation districts, insisted that the agency only filled the site with municipal garbage, as it was allowed to do.

He said the agency is going to recommend that its board of directors reject the claim.

“We see no basis for the claim,” Gulledge said. “We had contractual agreements at the time to fill the canyon with municipal solid waste and that was what was done. . . . We basically fulfilled all of our contractual agreements.”

The former dump fills part of a small canyon that runs across the rear of a dozen lots on Moccasin Lane, just off of Hawthorne Boulevard. Ron Beck, an attorney representing 18 homeowners, said that portion of the canyon was not supposed to be filled with municipal waste.

Further, Beck said, the site was supposed to have been plugged with earth fill that meets Rolling Hills Estates’ requirements for building sites.

“What’s there now is some bad material that has decomposed into some very dangerous substances,” Beck said.

However, Richard Thompson, planning director for Rolling Hills Estates, said he was surprised by the claim because agreements in the late 1960s between the city and the sanitation districts allowed the agency to fill the site with municipal waste.

“The question that remains is whether any toxic substances were put in there without permission,” Thompson said. “That is what is still to be determined.”

Several agencies have yet to complete studies at the site to determine whether hazardous or toxic materials are present, Thompson said.

The earthen cap on the landfill has sunk six feet in some places, damaging barns and corrals and releasing what residents say is noxious steam.

In addition, Rolling Hills Estates and air quality officials disclosed in late February that methane gas is leaking from the site at 20 times the allowable public nuisance standard set by the South Coast Air Quality Management District. However, officials said the gas poses no immediate explosive threat or health hazard to residents.

The dump was developed legally on private land by the sanitation districts in 1968, records show. It was quickly filled, then capped by a layer of earth, and the land subdivided and sold.

The back yards of 12 expensive homes along the north side of Moccasin Lane were built over the dump. By 1981, decomposition of yard trash and household garbage buried in the landfill was causing the yards to sink and crack.

In their claim, the residents said they suffered emotional distress, personal inconvenience and loss of property value as a result of the problems.