An elevator malfunction in Niagara Falls’ Skylon Tower stranded 18 people for two hours Wednesday night while firefighters worked to free them.

The glass-enclosed elevator was stuck near the peak of the nearly 800-foot tower, Niagara Falls Review reported.

“The Otis Elevator technician had to lower the elevator…he was able to open the doors manually,” Niagara Falls Fire Chief Jim Boutilier said.

Two passengers were treated by emergency responders for undisclosed reasons.

It wasn’t immediately clear what caused the malfunction.