Air samples show the following contaminant concentrations in an 8-hour shift (from 8: 00 a. m. to 4: 00 p. m.): 1. trifluorobromomethane, 0.1% from 11: 00 a. m. to 2: 00 p. m. 2. propane, 0.05% all day 3. phosgene, 1 part per million at 2: 00 p. m., with a duration of 15 minutes (a) assuming that no other contaminants are present, does the full-shift atmosphere meet osha standards? (b) to exactly meet osha standards, how much more or less time for the phosgene exposure would be permissible provided other contaminants remain as previously stated?