Students at Adelphi University were held in lock down for nearly 5 hours Tuesday, after a suspicious powder was found inside a classroom building. The substance turned out to be foot powder, Nassau County Police confirmed to PIX News.

University officials said about 110 students were kept in the building as a precaution, while investigators determined if the substance was safe. Some of the students were taking midterm exams at the time of the lock down.

Adelphi spokeswoman Kali Chan says the powder was found outside an office in Alumnae Hall.

Fire officials and Haz-Mat personnel were on the scene with decontamination tents in the event that students needed to be showered off.

"We are getting, hungry, antsy and frustrated," an unidentified sophomore told PIX News by cell phone during the 5-hour long lock down.

Students were released after the substance was deemed safe late Tuesday afternoon. Officials are still investigating whether the white colored powder was accidentally spilled or if it was planted with the intent to prompt a scare.

No injuries were reported.

The Long Island-based college has 8,600 students enrolled in at campuses in Garden City, New York City, Hauppauge, and Poughkeepsie.