The Ann Arbor VA Healthcare System has determined that a water main break was responsible for tiny "specks" of material found on and in cases that store sterile surgical equipment.
Nurses found the specks as part of a routine examination of the equipment prior to surgeries.
Public Information Officer Derek Atkinson says patients were given the option of rescheduling their surgeries, or going to a nearby hospital.
"If there are any emergency cases, those are being sent over to the University of Michigan right away," says Atkinson.
Michigan U.S. Rep. Debbie Dingell says the same hospital was investigated in 2014 for allegations of improper sterilization of surgical equipment.
She has asked the hospital for a report about the problem.
Atkinson says the Ann Arbor facility has received awards for patient safety. He says administrators plan changes to procedures to make sure a similar situation doesn't arise again.