Summerville High School students and staff are back inside and classes have resumed after the school was evacuated Thursday morning.
Pat Raynor, spokesperson for Dorchester District 2, says the fire alarm was activated and the school evacuated as a precaution after students and staff smelled smoke coming from a science lab.
The lab was not in use, according to Raynor.
The alarm was activated around 10 a.m., and staff and students left the building.
Summerville Fire Department responded and located the source of the problem.
Raynor says the fire department's initial investigation has revealed the smoke was coming from a burnt out exhaust fan in the lab.
The issue has been addressed, and the all-clear for students to return was given around 10:45 a.m., according to Raynor.
Students were outside for about 45 minutes.