The Department of Homeland Security’s inspector general found conditions at four immigration detention facilities that “undermine the protection of detainees’ rights, their humane treatment, and the provision of a safe and healthy environment,” a new 19-page report released Thursday revealed.

Based on calls from detainees to the Office of Inspector General Hotline, unannounced visits were made to six facilities. Inspections of five detention facilities raised concerns about the “treatment and care” of U.S. Immigration and Customs Enforcement detainees at four locations.