SAN JOSE, Calif. (KRON) — A Valley Transportation Authority (VTA) bus caught fire on Friday at a bus yard on Zanker Road, according to the San Jose Fire Department (SJFD). The bus had no passengers at the time of the fire.

Two VTA mechanics attempted to put the fire out but initially failed. They then pushed the bus out of the maintenance bay to avoid further damage to the surrounding building, officials said.

As first responders were arriving on scene, nearby employees in the building were evacuated. Crews were eventually able to extinguish the fire on the bus (photo above).

Two VTA mechanics suffered smoke inhalation and were taken to the hospital for treatment, the public transit agency said. The bus that caught fire was “damaged beyond repair.”

SJPD posted a video of crews responding to the bus that caught on fire. Watch the video in the media player above.

The cause of the fire is unknown at this time. Employees who were evacuated returned to their workstations after the fire was extinguished.

The bus that caught fire was one of the VTA’s 10 battery-electric Proterra buses. The other buses in that fleet have been removed from service pending an investigation into the fire.