DHS spokeswoman Sheree Powell said DHS officials have not yet seen the lawsuit and would not comment on it at this time.
DHS caseworkers are regularly assigned caseloads of more than 50 children each and sometimes as many as 100 children, when national standards call for limiting caseloads to 12 to 15 cases per worker, the lawsuit states.
"As a result, caseworkers cannot make required visits with foster children and caregivers, and cannot adequately monitor child safety," the lawsuit claims.
It also claims inadequate maintenance payments to foster parents contribute to a shortage of foster homes.
"For the past five years, Oklahoma has been among the worst three states in the nation, and for two years the very worst in the nation, in its rate of 'abuse in care' of foster children," the lawsuit states.
DHS officials have said in the past it is unfair to compare Oklahoma's child abuse rates with rates in other states because different states have different definitions of what constitutes child abuse.
Naomi was routinely separated from her siblings, who were also in DHS custody, and DHS employees failed to
They also state that DHS moved Naomi four times within seven months,