An office at Integris Baptist Medical Center was evacuated after a suspicious substance was found on an envelope in the mail.

The hospital is located at 3300 NW Expressway.  Authorities tell News 9 only a few people were evacuated from the office, and that Hazmat is investigating.

No patients required evacuation.

This is a developing story.

Keep checking with News 9 and News9.com for more information.