Penetration Of Methyl Isocyanate Through Organic Vapor And Acid Gas Respirator Cartridges.
Penetration of methyl-isocyanate (624839) (MIC) through organic vapor (OV) and acid gas (AG) respirator cartridges was evaluated. Two different OV and AG cartridges were tested for breakthrough at MIC concentrations of approximately 300 to 1,004 parts per million (ppm) and relative humidities (RH) of 0, 50, or 73 percent. Sorbent capacity of MIC in the OV cartridges was investigated. OV cartridges tested at 0 percent RH against 300ppm MIC had a breakthrough time of approximately 30 minutes, but the breakthrough concentration was approximately 20 times the threshold limit value, significantly different from the 0 percent RH data. At 73 percent RH, the onset of breakthrough for the OV cartridges was faster, but the rate of increase of breakthrough concentration with time was significantly reduced. AG cartridges gave breakthrough times of 60 plus minutes at 0 percent RH against 693 or 819ppm MIC. These cartridges showed instantaneous breakthrough when tested at 73 percent RH. MIC was weakly absorbed on charcoal in the OV cartridges. The authors conclude that the data supports and emphasizes the importance of NIOSH recommendations that any air purifying respirator should not be used for MIC.
NIOSH-Author; Lung; Inhalants; Ventilation; Lung-tissue; Air-monitoring; Respiration; Emission-sources; Pulmonary-function; Exposure-limits;
NTIS Accession No.
Division of Safety Research, NIOSH, U.S. Department of Health and Human Services, Morgantown, West Virginia, 63 pages, 15 references