| 1 | | | Hazardous Materials in the Cold Box/Warm Room (Copied from archived content) |
| O2 Displacement (Dry Ice Storage) | | Don't store Dry Ice in Walk-in Refrigerators | Walk-in refrigerators (or "cold boxes") typically recirculate the chilled air in their interiors, so storing volatile materials in them can pose unique hazards--any gases or vapors may concentrate inside.
Recently on the X Campus, a walk-in refrigerator was used to store dry ice. The dry ice was stored in a standard dry ice storage locker, but the locker had been placed in the cold box to further reduce the rate of dry ice loss. | The refrigerator builds up CO2 levels of 12,000 parts per million (ppm)! In comparison, outdoor air contains only about 400 ppm CO2, and OSHA's Permissible Exposure Limit for CO2 is 5000 ppm. Although no one was affected, the incident points out the need to keep volatiles out of walk-in refrigerators. | The dry ice, of course, gave off carbon dioxide (CO2) gas as it sublimed | Not mentioned |