? Clear Stream Elementary School in Valley Stream was evacuated Friday morning due to a gas leak.

The evacuation was ordered at around 8:30 a.m. after staff members noticed a strong smell of gas outside. The fire department says gas from a leaky pipe about 100 feet away from the school leaked into the basement .

"From the cold weather, the mains underneath the ground sometimes have a tendency to crack with age,? says John Beck, of the Valley Stream Fire Department.

Around 450 students were walked to Shaw Avenue Elementary School, located nearby, for the rest of the day. National Grid workers finished fixing the pipe and classes are expected to resume on Monday.

National Grid representatives confirmed the leak. A spokesperson tells News 12 Long Island the company is investigating and says in general all pipes are inspected every three years. National Grid would not confirm whether the pipe was old.

Some parents say they want answers as to why nothing was detected ahead of time. Valley Stream Public Schools Superintendent Dr. Elaine Kanas says she's waiting for more information, but the school will investigate the matter.