A growing number of union members at the six Daughters of Charity Health System hospitals in California have gone against their own union leadership and signed petitions in support of the sale of the hospitals to Prime Healthcare Services of Ontario, the hospital chain said.

In petitions and letters sent to Attorney General Kamala Harris, Service Employees International Union members urge her to support the sale to Prime in order to preserve the jobs of union workers, Prime said in a statement that did not name any specific members involved. Daughters of Charity claims that some union members have concerns about the actions of Dave Regan, president of SEIU-United Healthcare Workers West, who is attempting to block the sale.

Sean Wherley, a spokesman for the union, said that the union could not vouch for this claim, or quantify what percentage of its membership opposes the sale.

“All we know is that the many of our members have sent letters opposing the sale because of the history of Prime,” Wherley said. “I think the opposition is broader than is being presented. The opposition to this hospital sale is unlike any other we’ve seen before in the state of California.”

The Daughters of Charity board of directors approved the sale of its six California hospitals – including St. Vincent Medical Center near downtown Los Angeles and St. Francis Medical Center on Lynwood – to Prime in October, despite union opposition. The union immediately said it would fight the proposed sale, claiming that Prime has a record of buying up distressed facilities and then cutting patient services, hiking up prices and laying off workers.

If approved by Harris, the Daughters of Charity sale will add to Prime Healthcare’s 2.5 billion health system, which owns and operates 29 hospitals in nine states.