Fire and Emergency NZ says crews encountered an “unknown chemical” upon arrival at a school in Ashburton this morning.

Emergency services were called to St Joseph’s School just before 10am on Friday.

FENZ said it sent two crews from Ashburton and a HAZMAT crew from Timaru.

“Crews encountered an unknown chemical on arrival and are working with ambulance to make the scene safe,” a FENZ spokesperson said.

St John said it had sent an operations manager and ambulances to the school.

Two patients in a minor condition were taken to Ashburton Hospital.

The school has been approached for comment.