OSHA is enforcing the permissible exposure limit of 0.2 micrograms of beryllium per cubic meter of air and the short-term exposure limit
of two micrograms per cubic meter of air for general industry.
The device tracks, calculates and displays three cumulative formaldehyde gas metrics: 8-hour TWA (Time-Weighted Average), 1-hour average, and 15-minute STEL (Short-Term Exposure Limit
--MAC (STEL)--maximum admissible short-term Concentration--the short-term exposure limit
is an average concentration to which workers may be exposed without any adverse health effects if it does not last longer than 15 min and does not occur more than twice during a workday at interval not shorter than 1 h.
In the unpublished studies, phosphine gas reached 2.9 parts per million (ppm), three times the occupational short-term exposure limit
. Phosphine causes headache, pulmonary edema, and death.
The NIOSH Recommended Exposure Limit for C[O.sub.2] in workplaces is 0.5% (5,000 ppm) for a 40-hour workweek and 3.0% for a 15-minute short-term exposure limit
; a level of 4.0% is designated as "immediately dangerous to life or health" (2).