RIALTO - A multimillion-dollar legal drama between the city and San Bernardino County over who is responsible for a toxic underground plume may be nearing an end.

The sides appear close to an agreement that would settle the city's lawsuits against the county, according to sources familiar with the situation.

"I'm expecting good results. I really am," said Rialto Councilwoman Winnie Hanson, a member of the council's perchlorate committee.

The city and county are wrangling over the extent of the county's role in the contamination.

A federal lawsuit filed by the city against the county and dozens of other parties won't go to trial until October 2008 at the earliest. If a settlement is reached, the suit still will go to trial, but the portion of it involving the county would be settled.

In a second suit filed in San Bernardino County Superior Court, the city alleges the county expanded a landfill in violation of a 1998 agreement made when the county was expanding the Mid-Valley Sanitary Landfill. The settlement would put an end to that lawsuit.

The county is one of dozens of parties Rialto says are responsible for perchlorate contaminating local drinking water.

In 1997, the county purchased property to expand the landfill, which is contaminated with perchlorate, a toxic industrial chemical. Rialto says the work done on the property after the expansion caused the contamination to spread.

Perchlorate is used to

produce explosives and can harm humans by interfering with the thyroid gland.

Earlier in the week, Councilman Ed Scott sounded a more pessimistic note about the settlement. He had been saying for weeks the two sides would reach a settlement by Thursday.

At Tuesday night's council meeting and then again by phone on Wednesday, Scott said a settlement agreement between the two sides died somewhere on the county's end.

"We were assured that we would have something in place by the 20th so we could have some good news for our citizens," Scott said.

But county officials say work on a settlement is still moving forward.

"The county's lawyers are working on the settlement with the city's lawyers and our insurance company," Bob Page, 5th District Supervisor Josie Gonzales' chief of staff, wrote in an e-mail.

Gonzales' district includes Rialto.

Last year, a tentative settlement called for the county to pay the city roughly $6 million in exchange for the city dropping charges against the county, but the two sides could never agree on specifics.

Meanwhile, Rialto and the county are continuing to rack up legal bills fighting each other.

At its meeting Tuesday, the county's Board of Supervisors approved spending $400,000 in additional legal services related to perchlorate. Much of that money will go to investigate the extent of pollution, not just to lawyers.

To date, the county has spent $2.2 million on legal fees and $15 million for investigation and treatment, said county spokesman David Wert.