On Wednesday afternoon, the House Oversight and Reform committee launched an investigation into the Department of Justice’s recent decision to resume executions of inmates on federal death row. The decision, announced by Attorney General William Barr late last month, marked the end of a 16-year hiatus on federal executions. Now, House Democrats are demanding answers on how the administration arrived at its decision to bring back capital punishment, as well as details on how the DOJ plans on carrying out its executions.

Writing on behalf of the Subcommittee on Civil Rights and Civil Liberties, which is heading up the investigation, Reps. Jamie Raskin (D-Md.), who chairs the subcommittee, and Ayanna Pressley (D-Mass.) sent letters to Attorney General William Barr and Federal Bureau of Prisons Acting Director Hugh Hurwitz, asking for documentation and insight into how the lethal injections will be administered.

Of particular concern is the drug that will be used for the executions—pentobarbital sodium, a sedative. As Raskin and Pressley note, the drug has been used in Georgia, Missouri, and Texas executions, and has a patchy record in terms of efficacy and safety.

“Missouri reportedly purchased its pentobarbital from a pharmacy that has repeatedly been found to engage in hazardous pharmaceutical procedures,” the Democrats note, adding that Texas has reportedly used expired drugs in its executions.

“Additionally, though pentobarbital is supposed to be painless, five people executed in Texas using pentobarbital complained during their executions that they felt as if they were burning before they finally died. One inmate yelled, ‘I can feel that it does burn. Burning!’”

These reports are “particularly troubling,” the representatives write, “given the Department of Justice’s efforts to bar the FDA from regulating drugs used for executions.”

The DOJ’s return to capital punishment is out of step with current trends across the U.S. While 30 states currently allow capital punishment, more than a third have not used it in more than a decade, and federal executions are rare. As Raskin and Pressley note, only three prisoners have been put to death by the feds since 1963; the last person was executed by lethal injection in 2003, during George W. Bush’s first term.

As Mother Jones’ Nathalie Baptiste writes, European manufacturers began refusing to sell their drugs to U.S. prisons in 2010, with some specifically citing moral concerns. Criminal justice advocates have also argued that legal injections could run afoul of the eighth amendment’s prohibition on “cruel and unusual punishments.”

In 2014, then-president Barack Obama ordered a review of the death penalty, a report that the DOJ claims has been completed, though it hasn’t shared the results of the review. The subcommittee has also asked for Hurwitz and Barr to share the findings of the report.

The DOJ has already scheduled the executions of five men between December 2019 and January 2020.