The National Institutes of Health said on Thursday it had suspended operations of a facility that makes products used for clinical research after the discovery of fungal contamination in two vials of albumin.

Vials made from the same batch of albumin had been administered to six patients, though it is not known if those were also contaminated, the agency said. The six patients are being monitored and no signs of infection or illness have emerged.

Inspectors from the U.S. Food and Drug Administration (FDA) identified operational failures at the facility, including inadequate employee training and quality control.

The albumin was being used for the administration of the drug interleukin in clinical trials.

"The fact that patients may have been put in harm's way because of a failure to follow standard operating procedures in the NIH Clinical Center's Pharmaceutical Development Section is deeply troubling," NIH Director Dr. Francis Collins said in a statement, calling the situation "distressing and unacceptable."

The NIH said it will have to take several corrective actions, including appointing an external group of experts in microbiology and sterile manufacturing practices to review all standard operating procedures, policies, staffing and training.

An interim corrective action plan will be provided to the FDA by June 19, the NIH said.

The problem at the NIH comes on the heels of a U.S. military laboratory inadvertently shipping samples of live anthrax to 51 laboratories in 17 states and three foreign countries, and cases last year in which the Centers for Disease Control and Prevention (CDC) mishandled samples of anthrax and bird flu.

It also echoes a 2012 episode in which thousands of doses of steroids intended for spinal injections and produced by the New England Compounding Center were found to be contaminated with fungal matter. The tainted injections caused fungal infections, including meningitis, in 751 patients and killed 64, according to CDC.

According to the report of the FDA inspectors, some NIH workers failed to wear protective clothing intended to keep drug samples sterile. One had "an exposed wrist from a gap between their gloves and gown" as well as "exposed facial hair."

Equipment meant to keep contaminants out of the area where workers processed drugs was "deficient," the inspector found. For instance, no filter or screen covers a vent that connects the cleanroom to the roof 14 floors above.