PAWHUSKA, Oklahoma - Pawhuska School leaders continue to discuss a gas leak that has delayed the start of school for some students for more than a week.

Pre-K through sixth-grade students started class Monday, but high school and middle school students are still on summer vacation.

Outside of the high school and on a ball field, natural gas has been seeping from a geothermal well for two weeks.

The Oklahoma Corporation Commission said it doesn't yet know the source of the leak but said it wasn't caused by any break in a line.

Even though elementary school is close to the seeping methane, the Environmental Protection Agency said the air quality is safe there, so younger Pawhuska students - like first grader Tyler Howerton - got to start school.

“Go to school and make a lot of friends, go outside, have some fun,” he said.

Over the weekend, crews installed a ventilation system to continuously monitor the high school's air quality; but before class can start for all students, the fire marshal must give the all clear.

“For the safety for my kids, all kids, my grandkids, I'm glad they've taken the necessary steps to try to do what they need to do,” parent Jerry Howerton said.

Right now, there's no word from the district on when middle school and high school class with start.