Students at Kahala Elementary School were sent home Tuesday morning after a pesticide was accidentally released about a block away.

Firefighters were called to the school on Kilauea Avenue shortly after 9:30 a.m.

They received reports of a prominent, noxious chemical odor that affected several students and faculty members.

Two students sought treatment, according to the Department of Education. Emergency Medical Services says 17 children and three adults had to be monitored. Most complained of nausea, headaches and dizziness, though they did not need medical treatment.

“No one was actually poisoned by the chemical, it’s just the fumes are noxious and they make you feel like upset stomach and a little dizzy,” said Battalion Chief Geoffrey Chang of the Honolulu Fire Department.

Faculty and students were initially instructed to shelter in place in the school’s climate-controlled classrooms, but it wasn’t clear how long the odor would last, so at 11 a.m., the school was officially shut down and all students were sent home.

HFD determined that the fumes came from a nearby house that was being demolished. According to the Hawaii Department of Health, malathion must have been inside the structure.

Health officials say it’s not clear how much malathion was inside, but even a quart could have caused the problems the school experienced.

Experts say the site should have been checked for any harmful chemicals before demolition, and the property owner is supposed to hire a company to inspect for hazardous materials.

“They can come out check for any contaminants and file a report prior to demolition what steps need to be taken to contain the hazardous waste material,” said Chris Forbes of Island Construction and Demolition. “The demolition company should have asked first if the homeowner was aware of anything.”

We’re checking with the health department to see if any violations occurred.

School officials say classes at Kahala Elementary School will resume Wednesday.