“Normalcy” was the word of the day Friday as students and staff returned to Finch Elementary School, where dozens of children and adults began the week being treated for carbon monoxide poisoning.

“Today is a return to normalcy for our children,” said Steve Smith, associate superintendent for Atlanta Public Schools. “It’s an opportunity for us to return to a normal instruction day, in their own environment.”

The students of Finch attended classes the past three days about three miles away at Kennedy Middle School while authorities worked to determine the root of Monday’s carbon monoxide leak.

On Thursday, school system officials said that the failure of two maintenance workers to reopen a valve on a furnace after a Nov. 30 inspection was the cause of the leak, which sent carbon monoxide levels soaring to dangerous levels inside the Avon Avenue school.

The furnace, which officials said was damaged by the valve being left open, was replaced with a temporary one on Wednesday, and carbon monoxide monitors were installed in the building.

Friday morning, fire officials were at the school in force to make certain the carbon monoxide levels were normal.

“We wanted to come out here and assure that the school is safe,” Atlanta fire Capt. Dwayne Johnson told the AJC.

“We wanted to do a final reading and ensure that all the levels are at a safe level,” he said. “Everything came out negative, which is great.”

Principal Carol Evans said Finch is “probably the safest school in Atlanta Public Schools at this time.”

“Parents and children and staff, we’re all excited to return to school today,” the principal said. “This is our home, this is where we want to be and this provides the best opportunity for us to continue educating our children.”

Natasha Notae, the mother of a fifth- and second-grader, said, however, that her boys were not excited about Friday’s return to Finch.

“My eight-year-old really didn’t mind, but my 10-year-old didn’t want to come, because he’s very uneasy,” she said. “He’s still very shaken from Monday.”

Smith, the associate school superintendent, said the students — and parents — have nothing to worry about.

“We can tell them that it is absolutely safe for our children to be here,” he said.

Evans, who has only been principal at Finch since the beginning of this school year, said she was pleased with Monday’s orderly evacuation of the school.

“I think you can always, in hindsight, think, ‘well, maybe I could have done this or I could have done that,’ but overall, I think everything went really well,” the principal said.

“We have our drills every month, so our students knew exactly what to do,” she said. “We followed our routine procedures for evacuating the building, and everything went as well as it could have.”