SEATTLE (AP) – Officials say a potentially harmful fungus has been detected at Seattle Children’s Hospital, prompting a closure of the affected operating rooms.

The hospital says air tests last weekend detected the mold known as Aspergillus.

The hospital says the mold was present in several operating rooms and equipment storage rooms on the hospital’s main campus in northeast Seattle.

Officials say aspergillus is a common mold often present in the air, but in rare instances it can cause complications for surgical patients.

Officials say they believe the risk to their patients is very low but they will contact surgical patients who may have been exposed.

Officials are working with an outside industrial hygienist to investigate the mold’s source.

The state department of health has been notified.