Students and faculty were evacuated from the building do to a fire alarm Nov. 10 just after 8:00 a.m. during first period.

The alarm was later revealed to have been pulled by Assistant Principal Scott Morrison in response to an alarming smell in the science wing of MTHS. The smell was due to natural gas.

Natural gas is colorless and odorless; a substance called tert-butyl mercaptan is added to the gas to enhance its detection. Tert-butyl mercaptan, according to the Puget Sound Energy (PSE) website, smells similar to rotten eggs.

Setting off the fire alarm triggered the doors at the ends of each main hallway in the school to automatically close, containing the gas to rooms 220-229 and rooms 120-130.

“The school did a good job of evacuating… and we’re thankful for that,” Doug Dahal, battalion chief for Snohomish County Fire Department No. 1 (SCFD No. 1) said.

The gas lines were turned off and the science wing was ventilated, allowing students to move from the sports fields on campus and into the gym.

“I was impressed by how well behaved and mature the students were for that stretch of time [referring to the nearly two hours that students and staff were evacuated and waited outside and in the gym]. I felt that the immediate responses by the staff to our officials was the right response,” district spokesperson DJ Jakala said.

The PSE and the fire department deemed the science wing no longer a threat and cleared students to return to class by third period. There may have been some residual gas in some class rooms because there six students reportedly complained of headaches and nausea, two of whom chose to go home. According to the PSE website, tert-butyle merceptan can cause headaches and more serious conditions if one was overexposed.

MTHS prepares for fires and earthquake evacuations, but rarely has the school specifically prepared for a gas leak evacuation.

“Students and staff were amazing during the drill. The students were calm, orderly and patient. And the staff did an excellent job responding and attending to their responsibilities,” Principal Greg Schwab said.

Just in time for third period, students were cleared to leave the gym and return to class. Students were asked to return to their first period class, grab their things and proceed to their third period and continue with their day.