ELMWOOD PARK, N.J. (AP) — Authorities are still trying to determine what caused more than a dozen students to become ill at a northern New Jersey school last week.

Elmwood Park school officials have said a glycol leak from an HVAC unit on the roof at the Gantner Avenue Elementary School may have caused the students and some staff members to faint or feel sick.

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But speaking Tuesday night at a community meeting, they said a definitive answer hasn’t been found. Hazmat teams have been at the school monitoring air quality, but no other dangers have been detected.

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The school was evacuated Dec. 13 after a few students became sick. More students and some staffers became ill the next day, and the school was closed Friday for environmental and safety tests before it reopened Monday.

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