N2 used in a “purged-enclosure” for HAZLOC leads to O2 Defecient Atm

I have been writing a lot about the hazards of using N2 and CO2 in occupied spaces without adequate safeguards. This fatal accident occurred inside what many will call an “instrument shack” within a chemical process. This room had a gas chromatograph machine that was NOT intrinsically safe, so it was within a “pressureized enclosure” (NFPA 496). The primary source for pressurizing the enclosure was “plant air”, but it was backed up by N2. For reasons not stated by OSHA, the plant air lost pressure, and the N2 purge kicked on, as it’s designed to do, to keep the enclosure positively pressurized. At the time, the analyzers had 10 scfm of positive pressure from the instruments being purged into the gas chromatograph room. The system worked as intended to maintain positive pressure; however, the N2 vented into the occupied space, creating a fatal, oxygen-deficient atmosphere.

Employee #1 was placing name tags on testing instruments inside the gas chromatograph room at K-Line. The K-Line gas chromatograph was on a nitrogen backup for instrument air to keep its analyzers explosion-proof. At the time, the analyzers had 10 scfm of positive pressure from the instruments being purged into the gas chromatograph room. The gas chromatograph room’s atmosphere was therefore nitrogen-enriched when employee #1 entered to place the tags. The nitrogen replaced the oxygen in the room’s atmosphere, causing an oxygen deficiency. Employee #1 died of a lack of oxygen.

Source: https://www.osha.gov/ords/imis/establishment.inspection_detail?id=101020386