AUSTIN — Child Protective Services leaders have been forced to call in workers on overtime to check on endangered children this weekend, including in Dallas County.

It's the latest attempt to respond to mounting evidence that critical child welfare functions are crippled, especially in the state's biggest urban areas. Rapid turnover among child-abuse investigators and poor supervision have left CPS unable to keep up with vulnerable children.

In an email to agency leaders late Thursday, CPS field director Kim Gibbons announced the "face to face contact plan." It spelled out efforts — many of them new — to see children in Bexar, Dallas and Harris counties.

They include paying overtime to investigators and supervisors for several weeks; teaming workers with "special investigators" who formerly worked in law enforcement; and pleading with CPS workers elsewhere in the state to travel to Houston, Dallas or San Antonio to spend a week or more this month helping out.

CPS spokesman Patrick Crimmins confirmed that some investigators in the three target areas were ordered to work this weekend. Gibbons' memo was silent on the matter.

That "doesn't mean everybody, just whoever has kids they have not seen or who have not documented attempts or actual visits," Crimmins said in an email late Friday. "Getting to children who may be in danger before they are harmed is why CPS exists, and we obviously have to do a better job."

The moves followed Tuesday's release of data showing that statewide, as of Sept. 12, more than 4,700 children at risk of physical or sexual abuse or severe neglect had not had a required face-to-face contact with a CPS investigator.

The data indicates no region is more precarious than Harris County, which a Dallas Morning News investigation in May showed was headed for trouble due to enormous backlogs of child maltreatment cases.

In the Houston region last month, about 1,500 children believed to be at serious risk of harm or death — and who were supposed to have been seen within 24 or 72 hours, depending on the severity of the alleged mistreatment — had not had a visit from child abuse investigators.

Gibbons said 36 investigative units in Bexar, Dallas and Harris counties "are struggling the most" to make initial contacts and need help. That includes four in Bexar, seven in Dallas and a whopping 25 in Harris, she wrote.

While both Dallas and Bexar posted improvements between Aug. 15 and Wednesday in reducing percentages of unseen children, that wasn't true in Harris County, Gibbons wrote.

There, investigators through Wednesday had made face-to-face, initial contacts with 86 percent of children in "Priority 1" cases, the most serious. That was down from 87 percent on Aug. 15, the memo said.

According to CPS policy, no fewer than 95 percent of children mentioned in open cases are supposed to have been seen — within 24 hours for a Priority 1 case or 72 hours for Priority 2.

Gibbons appealed for workers in other regions to volunteer to spend at least a week in one of the three targeted urban counties.

That includes investigators, special investigators, other types of caseworkers, supervisors and even human services technicians who are eligible to become caseworkers under recently diluted educational requirements, she wrote — as long as their absence won't "cause an undue hardship on their county/region."

Last fall and winter, CPS helped stabilize collapsing investigations work in Dallas County by sending in workers from elsewhere — a move that may have contributed to newly emerging problems in other metro areas.

The goal is to work off the three big counties' backlog in less than a month, Gibbons wrote.

"Will meet targets by 11/4/16," she said.

Gibbons applauded what she called a team effort by the three affected regions to come up with improvement plans.

"Thank you all for being such an amazing team!" she said. "I appreciate how you have taken this on in such a solution focused manner and continue to do so. I look forward to watching the ongoing progress."