TULSA (AP) — Five foster children in the custody of the Oklahoma Department of Human Services were scalded in bath water, sexually molested, beaten with tree switches and belts and hit in the mouth — a pattern of abuse a child welfare expert called “outrageous and immoral” in a new report filed Wednesday in Tulsa federal court.

The 121-page review by consultant Peg McCartt Hess also quotes a foster parent of one of the children as saying, “If you don’t beat them down, they will run all over you.”

The document is the latest filing in the class-action lawsuit against the Oklahoma Department of Human Services filed last year by Children’s Rights, a New York-based child advocacy group. It accuses the department of mistreating some of the 10,000 or more children believed to be in the state system.

“Oklahoma is, quite simply, failing to keep its most vulnerable children safe,” Marcia Robinson Lowry, executive director of Children’s Rights, said Wednesday. “Far from being unique to the children named in the lawsuit, DHS’s pathetically deficient practices ensure that every abused or neglected child who comes into its custody faces an inordinately high risk of suffering further maltreatment on its watch.”

An attorney representing the agency did not immediately return a call seeking comment Wednesday afternoon.

For her report, Hess reviewed case files for five of the nine children named as plaintiffs in the lawsuit and found that all experienced neglect, physical and sexual abuse, and long, repeated placements in overcrowded and poorly run shelters.

She also noted the kids had only “superficial relationships” with DHS workers, which led to an increased risk of harm.

“When attempting to describe the children’s harm and suffering, the words that come to mind are incomprehensible, unimaginable, outrageous, and immoral,” Hess wrote of the cases. “These five young children’s tragic and painful stories, told in the pages of their DHS case files about their stays in DHS custody, need not have been written.

“These tragic stories were wholly preventable,” Hess wrote.

The 2008 lawsuit seeks a complete overhaul of the state’s child welfare system and alleges DHS has failed to provide for the basic safety of foster children in ways that “threaten their ability to live normal childhoods, to grow and develop and, in many instances, to even survive.”

Children’s Rights has proposed a remedy to the court that would limit caseloads for welfare workers, beef up training programs for employees and foster parents and ensure better monitoring of children in the state’s system, among other requests.