Last month during a congressional hearing, US Department of Health and Human Services’ Administration for Children and Families acting assistant secretary Steven Wagner told Congress that his agency was unable to account for 1,475 children who had been placed with sponsors between October and December of 2017. Though all the children unaccounted for showed up at the border alone, critics say Trump’s new immigration policy of separating children from their families to deter border crossings will only make issues like this worse.

Wagner indicated that the agency had been doing a routine checkup on 7,635 children and their sponsors when they discovered that about 19% were unresponsive to their queries. The department reports that there were also 19 cases of runaway children.

“I understand that it has been (Health and Human Services’) long-standing interpretation of the law that (the Office of Refugee Resettlement) is not legally responsible for children after they are released from ORR care,” Wagner told the committee during his testimony. He also stated that on average children usually stay in government custody for 56 days before being released to sponsor families, which can be comprised of family members, family friends or relatives.

Two years ago a Senate subcommittee released a report titled “Protecting Alien Children from Trafficking and Other Abuses: The Role of the Office of Refugee Resettlement,” which found that the Department of Health and Human Services turned over 8 children to human traffickers in Marion, Ohio, who then forced the minors to work in an egg farm and threatened them with bodily injury and withheld food, water, and paychecks.

Rob Portman, the Republican Senator from Ohio who served as the chairman of the congressional subcommittee told The New York Times, “It is intolerable that human trafficking — modern-day slavery — could occur in our own backyard… But what makes the Marion cases even more alarming is that a U.S. government agency was responsible for delivering some of the victims into the hands of their abusers.”

Wagner claims that the agency needs additional resources in order to take responsibility for children post-release, which would implicate the department in such cases going forward. He also says the department has taken steps to strengthen its protection of migrants in the system, including additional interviews and background checks.