It comes from this requirement in OSHA’s HAZWOPER standard and has sound logic behind it… (emphasis by me)
| 1910.120(q)(3)(iv) Employees engaged in emergency response and exposed to hazardous substances presenting an inhalation hazard or potential inhalation hazard shall wear positive pressure self-contained breathing apparatus while engaged in emergency response, until such time that the individual in charge of the ICS determines through the use of air monitoring that a decreased level of respiratory protection will not result in hazardous exposures to employees. |
I spend anywhere from 2-3 hours in a 24-hour Tech course. In my 40-hour Tech course I spend an additional hour just on Respiratory Protection because this single OSHA requirement is rarely fully understood by those attending a Tech level course. I teach this concept by asking…
What are the four (4) pieces of atmospheric-related data we MUST know to go from a Positive-Pressure SCBA (APF=10,000) used in LEVEL A and B ensembles down to a LEVEL C ensemble that uses an Air-Purifying Respirator (operating in a negative mode and has an APF of 50)?
Quite the change from an APF of 10,000 to 50, so we MUST fully understand these four (4) bits of data to assess the needed RP…
#1 – The hazardous substance involved
This may be easy to obtain in many cases due to the container labeling. But without proper labeling, this is 100% an UNKNOWN. In some cases, where I see a contradiction between how the HAZMAT is behaving once it exits its container and what the container label is saying, I will ALWAYS manage this as an UNKNOWN and an UNKNOWN environment is ALWAYS managed as an IDLH environment (1910.134(d)(1)(iii))