WALNUT CREEK — Some students debated in the dark. Others navigated pitch-black bathrooms equipped only with a small circle of light from their cell phones. A handful played Nerf football in the atrium, and many just blew off the day altogether.

Eventually, the Mount Diablo Unified School District decided to send them home; yet not before causing what one Northgate High School employee called an “unprecedented” day of chaos at the campus Monday.

“The teachers and staff at Northgate did a tremendous job, but they never should’ve been put in that position that they were in today,” MDUSD board member Brian Lawrence said Monday evening.

The school, like all others in the district, stayed open Monday despite the potential for leftover effects from the PG&E power shutdown over the weekend and the effect on air quality from several weekend fires. Unlike most others, Northgate did not gets its power back.

Most classes start at 7:55 a.m., but there is one Advanced Placement class that begins at 7 a.m. Shortly before 11 a.m. the students who stuck around were sent home.

“(Advanced Placement) Literature has about 10 people here,” English teacher Aliza Selinger said around 9:45 a.m.. “The classroom is pitch black. They’re debating whether it’s good for the school to be open or bad for the school to be open. They’re in the hallway.”

Calls and an email left with MDUSD Superintendent Robert Martinez were not returned immediately. According to employees, the decision to close the school came after a fire marshal from the Contra Costa County Fire Protection District toured the campus.

Multiple campus employees said they were aware the power might be out in the campus neighborhood early Monday and that no plan was in place.

“The district put Northgate High in a dangerous and unprecedented situation by sending students there in a blackout,” teacher Karen Jenkins said. “We made requests through the weekend to find out what would happen, and never heard a thing.”

Classes and some bathrooms at Northgate High are known for their lack of windows, and Jenkins said students used their cell phones to navigate them.

“Teachers showed up with head lamps,” Selinger said . “The kids handled it well. The teachers handled it well. The administration handled it the best they could. It was not their fault in any way.”

The MDUSD put out a statement by Monday afternoon that it was aware of the situation at the high school and that power also was out at Foothill Middle School on Cedro Lane and Walnut Acres Elementary School on Cerezo Drive. Calls to those schools Monday afternoon weren’t answered, but the district said in a statement to parents Monday that it planned to serve lunch there to students.

In the statement, the district also said it would give any students who missed a day an excused absence, because of the dirty air created by the ongoing fires.

About four-fifths of Northgate’s approximately 1,600 students went home “early on,” Selinger said, but about 300 to 350 still remained on campus around 10 a.m.

“It’s not complete mayhem,” she said. “But it’s not normal.”

Many of the students left before word came from the district that they could.

“Most kids have gone home,” Selinger said. “Some kids are wandering around. A couple are playing Nerf football outside in the atrium. I think the parents are livid. But this is not the administration’s fault. They’re following their instructions. They’re doing the best they can with all this.”

Winds were a bit calmer Monday morning, and PG&E said it had begun restoring power to affected areas that lost it Saturday night. Another power shutdown is possible Tuesday, when more heavy winds are expected to hit the area.