Pownal Elementary School was evacuated Friday morning when methane was detected during a routine check by Maine Natural Gas, which services the building.

Pownal Fire Department was called to the school just after 8:30 a.m.

Firefighters used meters to check the entire building but found no sign of any gas, according to Pownal Fire Chief Jesse Peters.

Students were taken to another school in Freeport until firefighters made sure the building was safe.

“I didn’t want them anywhere near that building,” Peters said.

Peters said methane was only detected outside the school. The source was the septic tank at the school.

Methane is a gas that can explode with the right concentration and an ignition source.

“It never made it inside (the school) and students were never in any danger,” Peters said Friday.

Regional School Unit 5 Superintendent Becky Foley said the staff was also evacuated. About 100 students attend Pownal Elementary School.

“It just was determined to be even safer and that we would all feel better just getting them away from the building and so we decided to evacuate them to Freeport High School, which is part of our safety plan,” Foley said.

Parents were notified with emails and robocalls. Foley said the evacuation went smoothly and students were back at school by lunchtime.

The methane, or sewer gas, was emitting from a manhole, Foley said.

“This is not any real reason for concern,” she said. “I think anytime you’re talking about natural gas, I’m always going to err on the side of caution.”