Randolph — A 63-year-old Braintree, Vt., man has been arrested on an aggravated assault charge involving a co-worker at Gifford Medical Center.

Wayne Parezo allegedly introduced a “foreign substance” into a woman’s beverage, according to a Friday news release from the Orange County Sheriff’s Department.

Because the investigation is ongoing, Capt. Kyle Kapitanski of the sheriff’s department declined to provide more information about the type of substance involved. But he said the victim “is OK” after a trip to Gifford’s emergency room, and there is “no cause for any public alarm.”

Parezo was a Gifford employee at the time of the July 25 incident, Kapitanski said. A 2016 Gifford publication said Parezo worked in environmental services at the Randolph-based hospital.

He is no longer employed there, Gifford spokeswoman Maryellen Apelquist said in an email Friday.

Parezo is scheduled to be arraigned in Orange County Superior Court on Sept. 5.