At about 11:15 am, the Honolulu Fire Department began receiving calls about a strong smell of gas -- like propane -- at three different locations in Waipahu.
The hardest hit appeared to be Waipahu Intermediate, where five adults and two children complained of nausea, shortness of breath and other symptoms. Paramedics transported them to a hospital for further evaluation.
About 1,230 students and 95 staff members were evacuated from the school buildings until the all-clear was given about an hour later. Fire officials described the odor as transient, meaning it had come and gone before investigators could pinpoint the source.
"It's going to be a little bit of a slow and methodical process to try and find out what happened, especially after the fact where there's no continuation," Capt. Terry Seelig, Honolulu Fire Department, said. "That makes it difficult."
"I just had a meeting with the staff and the students, and I congratulated them on their behavior and executing the drill because we practice the drill and executing the real-life experience," Gary Fujii, school vice principal, said.
A Gas Company worker was on scene to assist in the investigation.