I wonder if there were any HF tanks nearby.
Vital in so many processes, yet the fear of HF acid is drilled into everybody's heads before being allowed to put on a bunny suit to even go into the Fab. This appears to be an Ingot facility, so they may keep the HF far, far away.
(To those not familiar, we are talking about the Hydrofluoric Acid used to make the circuits on the wafers. It's colorless, tasteless and it feels like water on your skin. It's absorbed into the skin and creates intensely painful lesions. If you got more than a small splash in you, it invades the internal organs, sucking all the electrolytes out, eventually causing heart failure and death. It's serious business.)