CHICAGO — All adults who work in Chicago public schools will undergo new background checks before classes begin this fall, CPS announced Friday.

That includes employees, coaches, volunteers and vendors.

The move comes after a Chicago Tribune investigation revealed CPS failed to protect hundreds of students who were sexually abused by school employees. According to the newspaper, teachers and principals often failed to alert child welfare investigators or police when students disclosed abuse — despite the state’s mandated reporting law.

According to CPS, all adults who regularly work with children were required to undergo background checks during the hiring process. Until now, employees were never re-checked once on the job.

In a news release Friday, CPS said it also plans to conduct periodic background checks moving forward and to train all athletic coaches using the same standards.

Anyone who has not undergone a new background check by fall will not be allowed in schools.