Tappan Zee High School is open as usual this morning, hours after a hazmat incident last night.

Fire officials say they were called to the school after a cleaning contractor was using some sort of acid-based solution to clean the ladies room near the building's main entrance. That cleaning solution reacted with an unknown substance in the bathroom to create a toxic gas. "It reacted wrong and created some type of fog, it set off a detector in the school," says Pete Burn, of the Orangeburg Fire Department.

The few people who were in the school, mostly janitorial staff, were evacuated and all got out safely.

However, two volunteer firefighters were sickened by the fumes and had to be taken to the hospital. They are expected to be OK.

The Rockalnd County Hazmat team was called in, and they were able to neutralize the acid.

Classes are in session as scheduled today.