WARWICK, R.I. (AP) — Authorities say six people received treatment after coming into contact with an unknown substance near the Community College of Rhode Island.

Police say an officer and a civilian employee were conducting a wellness check Thursday afternoon at a homeless encampment in Warwick when they were exposed to the substance. The officer called for backup after feeling sick, and four other officers responded to help.

Police say the first officer was treated at the scene with the opioid antidote naloxone. All six people were hospitalized as a precaution.

A spokeswoman for the college says classes were not affected.

The substance is being tested.