Power Outage

In the event of a power outage, laboratory instruments and engineering controls may no longer provide the level of protection they did while being powered. Two examples of this behavior are fume hoods and laboratory refrigerators and freezers. Fume hoods may not receive emergency power and will cease drawing vapors away from the laboratory. Refrigerators and freezers containing volatile chemicals will eventually increase in temperature, potentially creating a hazardous environment inside the body of the instrument.

Take the following precautions when the power is off:

1. Shut down experiments and processes involving hazardous chemicals.
2. If equipment failures create hazardous conditions, notify EHS immediately.
3. Fume hoods
   1. Stop operations emitting hazardous vapors, fumes, or infectious agents
   2. Cap open containers
   3. Close the safety sash
   4. Check for adequate airflow once power returns.
4. Refrigerators and freezers
   1. Transfer volatile chemicals from cold rooms and unpowered units to an operational refrigerator or freezer.
   2. Transfer dry ice to refrigerators and freezers to keep materials cold. Do not use dry ice in walk-in coolers or confined spaces.
   3. Do not open units until transferring material or adding dry ice. An unopened unit may stay cold for several hours.
   4. Once power returns, keep doors on units closed until working temperatures have been restored.

https://blink.ucsd.edu/safety/research-lab/laboratory/power-failure.html#3.-When-the-power-returns