Natural gas leaks Tuesday morning at Merced High School disrupted the morning schedule, sending students and teachers home at midday.

A small gas leak was found about 8:10 a.m. in a science classroom, and the 300 wing was evacuated, with some students temporarily relocated to the cafeteria, gymnasium and senior quad area.

Principal John Olson said the main natural gas line to the campus was shut off about 10:30 a.m., with Merced Fire Department and Pacific Gas & Electric Co. crews dispatched to the West Olive Avenue school.

Ultimately, it was decided to dismiss the school's 2,700 students at 12:24 p.m. and teachers a half-hour later. Buses ran their normal routes, just earlier than usual.

A campus maintenance worker doing a job near the science classroom initially detected a faint smell of gas that had accumulated overnight. A natural gas fitting was then repaired, Olson said.

Administrators and maintenance personnel used a "sniffer" to see if there were any other leaks. During this process a natural gas leak was detected in an underground pipe that runs parallel to the sidewalk in front of a classroom.

Plumbers used a backhoe to excavate the pipe and make repairs. Pipeline repairs were expected to take three to four hours. Olson said later Tuesday that school would resume on schedule today. Phone messages in English, Spanish and Hmong were sent to parents informing them about the resumption of classes.

The Fire Department determined the campus was free of hazards before allowing school to resume.

Olson said two affected areas were tested, and not even trace levels of natural gas were detected.

Olson said evacuations were handled in an organized and orderly fashion.

"I'm thrilled with the way the kids responded," he said. "There were no issues and there was no immediate threat. Not at any time was there any danger."

Battalion Chief Don Roe of the Merced Fire Department said a fire truck stayed on campus most of the day to monitor the repairs. Wind currents were moving pockets of natural gas around the complex, necessitating the shutdown.

Gas leaks don't happen often, Roe said. With natural gas, there are explosive hazards along with risks of asphyxiation and carbon monoxide poisoning.

Low temperatures in natural gas lines, which are about 50 years old, could have played a role in the gas leaks, Roe said.

Sandy Schiber, assistant superintendent of human resources for the Merced Union High School District, commended Olson for his work with emergency responders. Schiber, PG&E representatives and maintenance personnel went from classroom to classroom to search for natural gas odors.

Nicole Liebelt, PG&E spokeswoman, said the utility dispatched a gas service representative who assisted in locating the gas line break. She said it was up to the school to make the necessary repairs because the problem is on school grounds.

Liebelt said any time a customer smells gas, he or she should call PG&E. She said representatives are happy to come out and assess the situation.

Reporter Doane Yawger can be reached at (209) 385-2407 or dyawger@mercedsunstar.com.