As deaths among abused and neglected children have mounted in recent months, Los Angeles County supervisors and their aides have summoned child-welfare director Trish Ploehn to lengthy closed-door sessions to explain what’s gone wrong in her department and how she plans to fix it.

“The safety and security of the children within our child-welfare system is the most important part of her job,” Supervisor Zev Yaroslavsky said last week. “This is a matter of great urgency for her and the Board of Supervisors, and we will all be judged by the results.”

The department’s problems, however, surfaced long before Ploehn was promoted to the top job in 2006, becoming the third chief since 1999. More constant has been the board that chose her, four of whose members have served for at least 14 years.

Time and again, when children under the county’s watch have died or come to harm, the supervisors have called for reforms and turned up the heat on department chiefs -- leaders they picked. At least two of Ploehn’s predecessors left under fire, with one remarking on his way out that it was the toughest job in the country.

The troubles of the nation’s largest county-run child welfare department remain, many of them substantially unchanged.

“I will say, categorically, that the L.A. County Board of Supervisors is the greatest culprit,” said community activist Earl Ofari Hutchinson, who has also called for Ploehn’s firing.

“All of this is on their watch,” he said. “It’s their agency, and they have direct supervision and oversight of it. . . . If I see one more ‘We’re going to review it’ from the Board of Supervisors, I’m going to scream.”

In early 2000, after a task force reported that the county’s foster care system -- then overseen by child-welfare director Anita Bock -- was in disarray, Supervisor Michael Antonovich said it “cries out for reform.”

Four years later, Supervisor Gloria Molina hammered then-director David Sanders after the fatal beating of a Canoga Park child who was allowed to stay with his mother despite six previous complaints of abuse.

“Let’s not kid ourselves,” Molina said. “This is about people not doing their jobs. . . . The same ill-trained, ill-prepared social workers could have hurt other people. Don’t you consider it a dangerous situation when you have something as blatant as this?”

Six years later, questions about training and deadly oversights still dog the department.

Under Ploehn, a 30-year department veteran, the agency’s failings have come to light more readily than in the past, largely because of a state law that opened previously confidential records. Before the law took effect in 2008, virtually all information about children’s deaths from abuse or neglect was kept from public view, ostensibly to protect the privacy of victims and their families. Reports about horrific cases leaked out sporadically.

The recent records show that about 35 children from families previously investigated by the department have died of abuse or neglect by their caregivers since January 2008.

When The Times reported last April that 14 such deaths had occurred in 2008 alone, supervisors expressed shock and outrage. But Yaroslavsky acknowledged the next day that the board had been aware of similar numbers in previous years.

A Times investigation last year also showed that supervisors and administrators had been explicitly warned over a period of 18 years that children were dying or being injured in part because agencies within the county weren’t communicating.

Nonetheless, the number of recent cases, and their tragic details, have caused some to question Ploehn’s abilities and whether she has the management team in place to get results.

She’s had years to shape the department, having been named deputy director in 2003. Yet when asked to explain high-profile mistakes by her staff, she sometimes appears unfamiliar with the details or withholds information, even from the board, according to two sources familiar with the matter who spoke on condition of anonymity.

Today, key posts in the department remain vacant, including that of top deputy. Important county departments have yet to join a computer system designed to share vital case information. And, citing budget problems, supervisors have denied Ploehn’s request for hundreds of new social workers she says she needs.

Concerns about the department’s performance were punctuated March 20 by the fatal beating of Deandre Green, 2, allegedly by his mother’s boyfriend. The boy’s father later told The Times that police and child-welfare officials were warned at least twice in recent months about possible abuse.

Earlier this month, 2-year-old Viola Vanclief was killed while in the care of a foster family agency that had a history of child-abuse incidents. Viola had been placed with the foster mother even though the woman had been the subject of five previous child-abuse complaints and her boyfriend was a convicted felon.

Such deaths have often shared persistent threads: social workers who did not follow procedure or did not have the information to make a proper assessment.

Before these cases surfaced, Ploehn, 55, had been widely credited for quickly recognizing the severity of the child-death problem and for plunging into efforts to fix it. Key to her plan were better technology to arm social workers with more information during investigations, the proposed addition of 300 social workers to the investigations unit and a far more intensive training academy for staffers.

The overwhelming focus on the deaths, Ploehn said, has obscured her department’s good works.

“Our department is saving children’s lives and preventing children from further abuse,” she wrote in a statement to The Times.

“Each year, we receive 160,000 to 180,000 referrals to our child-protection hotline. We’ve experienced exceptional successes and gains in reforming child welfare, reducing the number of children in out-of-home care, and reducing timelines to permanency, reunification and adoption.”

John Tanner, executive director of Service Employees International Union 721, which represents county social workers, credited Ploehn for listening to his group’s reform proposals, despite the growing pressure on her and the department. He warned against firing Ploehn, saying it would destabilize reform efforts and repeat a pattern of scapegoating department heads.

“It’s well known that there are seven departments led by interim directors. There have been six Department of Health Services directors over 15 years,” he said, counting two acting chiefs. “Trish is pushing change. Everyone wishes it would come faster, but I still think she deserves support.”

One of her most stalwart backers, Supervisor Don Knabe, called her “a remarkable leader even under the most enormous pressure” and vowed his continued support.

“I have worked with her for many years going back to her days in the Torrance office, long before she became head of the department a few years ago,” he said in a statement. “She was the right choice then and she remains the right choice now.”

It would be unfair to blame all of the department’s problems on Ploehn, some experts say.

Eileen Mayers Pasztor, an associate professor of social work at Cal State Long Beach who has trained thousands of child-welfare professionals and advocates nationwide, contends that accredited agencies elsewhere have more rigorous standards. But they also have more support.

“We cannot expect well-meaning public and private child-welfare agencies to achieve outcomes that are not commensurate with the resources provided,” she said. “That is not fair, and it’s not right -- especially for the children.”

But some critics, including Hutchinson, president of the Urban Policy Roundtable, think it is time for Ploehn to go.

“From the track record of this organization, it is clear that it is time for a total management shake-up, and that begins with the director,” he said.

garrett.therolf @latimes.com

kim.christensen @latimes.com