THE BUREAU of Prisons claims to have a policy prohibiting solitary confinement, as it should. But then what do you call locking up inmates by themselves in single cells for more than 22 hours a day for long periods of time with no or limited engagement with others? According to a new report, that is precisely what the federal prison system does with thousands of prisoners. We would call it solitary confinement. It would also be accurate to call it torture. And it would be fair to ask: Will a scathing report from the Justice Department’s inspector general finally impel officials to put an end to this inhumane practice?

“Although the BOP has stated that it does not practice solitary confinement, we found inmates, including those with mental illness, who were housed in single-cell confinement for long periods of time, isolated from other inmates, with limited human contact,” wrote Inspector General Michael E. Horowitz. Restrictive housing placement is the bureau’s preferred terminology, but the report released last week made clear that is a semantic dodge. According to the inspector general, 9,749 inmates — 7 percent of those confined by the Bureau of Prisons — were in some form of restricted housing in June 2016. Among those forced to languish alone were inmates with serious mental illness, some of whom were isolated for more than five years.

A number of state prison systems have taken steps to limit or end their use of solitary confinement because of mounting evidence of its detrimental effects. The inspector general cited research that isolation can cause anxiety, depression, anger, paranoia and psychosis among prisoners. “You have no contact, you don’t speak to anybody, and it’s a form of torture on some level,” a psychologist at one prison told investigators. Ending such barbarity is not only morally correct but also has practical benefits in improving public safety. Prisoners subjected to solitary confinement have difficulty reentering society and are more likely to re-offend.

The report outlined a series of recommendations that the agency agreed to, including establishing policies on the use of restrictive housing, tracking its use, setting limits and better documenting prisoners’ mental-health diagnoses. Normally an agreement to take such steps would be encouraging. But given that the bureau denies practicing solitary confinement, any promise to cease the practice has to be monitored closely. It will be essential for the inspector general to follow up and for Congress to be diligent in exercising oversight.