I will remember your expertise, what caused the smoke in the command center when there was no fire?
When you have a -48V power supply that can supply nearly 5,000 amps, you must be very careful around the power bus. The bus is usually made from 6 to 8 plates of laminated aluminum to afford sufficient stiffness. When the power goes on, the sudden rush of current causes a strong magnetic field that would whip a flexible conductor around. There is enough current to vaporize a typical steel crescent wrench if dropped across the bus.
The smoke could have come from a piece of electronic equipment that was improperly connected to the power or a shorted power supply cable. The latter case might have necessitated an immediate power shut off to avoid escalation into an actual fire.