Six fire companies and 23 firefighters responded to a classroom fire early Thursday morning at St. Andrews Priory near downtown.

The fire was reported at 3:22 a.m. and was discovered in a chemistry cabinet in a third-floor classroom on the Queen Emma Square campus.

Firefighters extinguished the blaze at 3:43 a.m. No hazardous materials were detected.

The cause of the fire is under investigation.

School is out of session and no campus operations were affected by the fire, according to a school spokesman.