OCOEE, Fla. -

Health Central in Ocoee returned to normal operation Monday night after being shut down due to a possible hazardous materials situation.

Officials said one patient was treated after possibly being exposed to a hazardous material at the medical office building adjacent to the hospital.  The woman said she had received a piece of mail she felt to be suspicious, so she brought it to her doctor.  The handling of the mail caused the hazardous materials situation.

That woman was treated and released, and the mail tested negative for hazardous material. 

The FBI was called to the scene per protocol and will run biological tests on it.

Orlando Health, which owns the Health Central hospital, diverted their ER patients during the time it was shut down.