Operating rooms at Windsor Regional Hospital-Ouellette Campus are expected to remain closed until at least Tuesday.
The hospital cancelled all elective surgeries Monday night after noticing staining or "scorching" on cloths used to wrap sterile instruments.
Hospital officials say two independent laboratory tests confirm that the markings are organic in nature, not harmful and do not negatively impact the sterilization of the instruments.
They believe the markings are coming from steam lines that run from the powerhouse to the autoclaves-the sterilizing machines. They plan to solve the issue by applying additional filters to the steam system.
Full tests need to be completed on the system to determine if the proposed solution will fix the problem. Hospital officials say they will not be in a position to do that until late Friday.
The hospital hopes to have the operating rooms up and running at normal capacity by Tuesday morning.