Staff at the Minneapolis Veterans Affairs Medical Center found "an unidentified substance" in the hospital's sterilization equipment Wednesday, prompting the hospital to stop surgeries, according to the Star Tribune.
The VA has sent the mystery substance to a lab for testing.
Other hospitals in the area, including the University of Minnesota Medical Center, are taking in urgent and emergency cases from the VA facility, according to the report, and other surgeries have been rescheduled.
The Minneapolis VA hospital is still able to perform some surgeries that do not involve the sterilizing equipment.