MONTPELIER (AP) - Vermont Gov. Peter Shumlin said Wednesday he was ordering the Department of Children and Families to do more to protect children in the aftermath of the deaths of two toddlers whose family circumstances had prompted department involvement.

Shumlin said he was beefing up the agency's staffing levels to reduce workloads, which have doubled in the last five years as the state has struggled with heroin and opiate drug problems.

He also said he would increase training for social workers and the oversight of cases in which children in state custody are returned to their families. In addition, his plan calls for a review of the department's structure to make sure it's operating efficiently.

The changes come in the aftermath of the deaths of 15-month old Peighton Geraw, of Winooski, in April and 2-year-old Dezirae Sheldon, of Poultney, in February.

Peighton's death has been ruled a homicide; no charges have been filed. Deziare's stepfather has been charged with second-degree murder, and has pleaded not guilty.

"It breaks my heart. I know it breaks the heart of all Vermonters when we lose a vulnerable child to someone who is so empty-hearted that they would take that child's life," Shumlin said during a news conference. "In both the cases of Dezirae and Peighton, we as a state have failed."

Shumlin refused to discuss the specifics of the cases because they remain under investigation.

The department was created in 2004 out of two other organizations. It currently oversees a number of state agencies that provide services to more than 200,000 Vermonters.

Since 2008, the number of child abuse investigations has doubled. Staff reductions that pre-date the Shumlin administration are being reversed, but the social work caseload - about 17 for each social worker - is still well above the Legislature's suggested ratio of 12 to 1.

Shumlin's order included: a review of the department's structure by Human Services Secretary Douglas Racine by Aug. 1; the recruitment of 18 social workers and six substance abuse screeners; an increase in the department's central office staff; an increase in the training of social workers, law enforcement, lawyers, the judiciary, medical community and others who come in contact with vulnerable children; a central office review of all cases in which the agency is considering returning a child in state custody who has suffered serious physical abuse to a parent.