ORANGE, Calif. —  A woman who reported being ill dropped a mysterious substance on the floor of an emergency room on Friday, forcing the unit to shut down for several hours until tests confirmed it was only powdered alfredo sauce.

A police officer responding to the scene also reported feeling sick when he came into contact with the substance at St. Joseph's Hospital, Orange Fire Capt. Ian MacDonald said.

The officer and the walk-in patient were quarantined and ambulances were diverted to other hospitals for about four hours while a hazardous-materials team tested the powder.

It turns out the contents of the bag were "an empty herbal vitamin package with residue still inside and powdered alfredo sauce mix," MacDonald said.

Adams could not explain why investigators and the patient failed to communicate about what was in the plastic bag, but he said medical workers were evaluating her for mental health problems.

"We had certain red flags — an unknown subject walking into an emergency department with unknown substance. And after she was feeling ill, an officer felt ill. With that criteria, we were treating the incident as a worst-case scenario," MacDonald said. "It turned out to be a best-case scenario."

MacDonald said the patient and the officer were in good condition.

Police Sgt. Dan Adams said the officer who responded "didn't feel as ill as everyone thought he did. He just reported a sore throat."

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