Migrants seeking asylum and being held at an overcrowded US Border Patrol facility in Texas could become violent due to the inhumane conditions, an internal Department of Homeland Security watchdog found.

The El Paso Del Norte Processing Center in West Texas had packed 900 people into a building meant to hold just 125 when the agency’s inspector general made a surprise visit to the facility in early May, according to a report released Friday.

One cell built to hold 12 people contained 76 migrants, forcing detainees to stand on toilets to find room to breathe.

“Border Patrol management on site said there is an ongoing concern that rising tensions among detainees could turn violent,” the report found.

On Wednesday, Border Patrol caught 1,036 migrants illegally crossing the U.S.-Mexico border near El Paso —largest single group ever.