A pesticide sprayed in a yard across the street from 'Aina Haina Elementary School sent more than 40 students to five Honolulu hospitals yesterday afternoon for observation.

Aside from one child who vomited as a result of the pesticide fumes, the worst symptoms were nausea and watery, itchy eyes, said Greg Knudsen, spokesman for the state Department of Education. None of the schoolchildren were seriously ill, he said.

School principal Susan Okano declined comment yesterday.

The children were kept after school longer than usual to ensure that enough time had passed for the fumes to dissipate, Knudsen said. Children enrolled in the A-Plus after-school program were on campus yesterday afternoon as fire and hazardous-materials personnel were on the scene investigating.

The incident was the second in a little more than two months involving the house-and-garden pesticide malathion and an elementary school.

On Feb. 28, a Honolulu fire hazmat crew was called because a resident poured malathion on her driveway on Ho'ono Street, creating a chemical odor at Waiau Elementary School. Two schoolchildren became ill from the fumes and were treated by city Emergency Medical Services paramedics.

Yesterday about 20 firefighters responded to a call from 'Aina Haina Elementary and found about 15 children suffering from nausea, dizziness and itchy eyes. By the time firefighters found the yard on Makalena Street that was treated with malathion and managed to reduce the potency, 44 children were claiming discomfort, Fire Department Capt. Kenison Tejada said.

"I don't know of any of them that were serious," said Tejada. "It has happened before."

EMS technicians ferried the children to five hospitals in two city buses for tests, Knudsen said.

Malathion is a brownish-yellow liquid that is used to kill insects on farm crops and in gardens, treat lice on humans, eradicate mosquitoes and rid pets of fleas, according to the U.S. Department of Health's Agency for Toxic Substances and Disease Registry.

Exposure to high amounts of malathion can cause difficulty breathing, tightness of the chest, vomiting, cramps, diarrhea, sweating, blurred vision, headaches, dizziness, loss of consciousness, and in extreme doses, death, according to the agency.

Reach Peter Boylan at pboylan@honoluluadvertiser.com.