Reports say up to 20 people have been treated after what authorities are calling a 'mass casualty' event at Exeter Hospital.

According to several news outlets, emergency crews from several surrounding communities were dispatched to Exeter Hospital shortly after 11am Friday.

The incident began after both patients and staff started to complain of nausea and dizziness.

WMUR reports crews had to evacuate a portion of the hospital including the ER and OR. The initial call was for a suspicious odor. The cause is currently under investigation.