A community activist has filed a lawsuit against the County of Sonoma seeking to halt the sale of the county’s old Chanate Road hospital complex.

The complaint, filed Monday in Sonoma County Superior Court by Roseland neighborhood advocate Duane De Witt, claims the sale of the property would benefit developer Bill Gallaher at the expense of the indigent and homeless.

An attorney for the county said there was no legal basis for the lawsuit.

The complaint seeks a court order to bar the sale of the 82-acre site, which is home to the county’s public health lab, morgue, a county mental health clinic, a women’s shelter, a mental health wellness center and a bird rescue center.

The Board of Supervisors on Tuesday tentatively approved the sale to Gallaher, who wants to build up to 800 new housing units on the property.

A final vote is scheduled July 11. Supervisors were unanimous in their support of the sale Tuesday, with some saying the property had become a liability needing costly plumbing, mechanical and electrical repairs.

De Witt, however, said such claims are justification for what he called a “giveaway” of public assets.

“Anyone who understands health care in this county knows we need those facilities at the Chanate complex. It’s not the liability they say,” he said. “On the contrary, it’s an asset and a much-needed health care resource.”

Ronald Young, described by De Witt as a local homeless man, is listed as a co-plaintiff in the complaint. Their suit claims the county is asking far too little money for the property.

On Tuesday, county supervisors approved a cash sales price of up to $11.5 million, but pointed out that the actual financial benefit would be far higher.

The county says the local community would benefit from between $24 million and $48 million in affordable housing, depending on the number of units Gallaher ends up building.

Debbie Latham, chief deputy county counsel, said it is “not entirely clear what the legal basis” is for the lawsuit. She said the county had yet to be formally served with the complaint.

“We don’t believe that there’s any legal basis to challenging the board’s actions,” she said. “There’s a statutory process to dispose of the property, and the county has followed that process.”

De Witt, who worked as a respiratory care practitioner at the county-run hospital complex before its operations were transferred to Sutter Health in 1996, said it was irresponsible for the county to dispose of a facility that had served the local community for many generations.

County officials, however, say those services will be relocated to other buildings owned by the county. The morgue and public health lab will remain at the Chanate complex without paying rent for at least the next five years, officials said.

You can reach Staff Writer Martin Espinoza at 707-521-5213 or martin.espinoza@pressdemocrat.com. On Twitter @renofish.