Hickam Elementary School will be back in session today after authorities traced the source of a noxious odor that prompted the evacuation of the campus Thursday morning.

The culprit: a bilge and oily water treatment system that was being repaired nearby.

All 613 students and 75 adults were evacuated Thursday morning after the strong chemical odor was detected on the campus, which is on Joint Base Pearl Harbor-Hickam. They moved to Nelles Chapel and classes were canceled.

Naval Facilities Hawaii staff, federal firefighters and base security officers responded to the scene and located the source of the smell.

“We are thankful there were no injuries or serious illnesses today, and we are grateful to the first responders,” said Capt. Jeff Bernard, joint base commander. “I want to assure parents that we will do everything possible to prevent another incident in which we have to remove students from the school.“