The company has six welding booths, or areas that are partitioned only for the use of welding curtains. The booth is open to mixing in the front and...

The company has six welding booths, or areas that are partitioned only for the use of welding curtains. The booth is open to mixing in the front and top. The company is worried about the welder's exposure to iron oxide (PEL 10 mg/m³). For a valid sample, you must have a minimum of six hours of sampling (The remaining two hours of the work day is considered to be equal to or less than the sampled exposure. As a result of your air sampling over an eight-hour time period (i.e., the work schedule), you receive the following analytical report:

Name Location Conc. 1 Time 1 Conc. 2 Time 2 Conc. 3 Time 3 Anne Welding Booth #1 4.3 mg/m³ 150 min. 3.7 mg/m³ 150 min 2.2 mg/m³ 240 min OSH 4308, Advanced Concepts in Environmental Safety Management 2

Frank Worldly Booth #2 2.1 mg/m³ 180 min 2.8 mg/m³ 120 min 3.1 mg/m³ 240 min Jim Young Booth #3 1.7 mg/m³ 205 min 1.25 mg/m³ 125 min 1.03 mg/m³ 150 min Betty Johnson Booth #4 12.8 mg/m³ 165 min 11.2 mg/m³ 72 min 9.8 mg/m³ 123 min Jack Jones Booth #5 7.8 mg/m³ 190 min 14.2 mg/m³ 149 min 8.8 mg/m³ 140 min Joey Apperton Booth #6 3.9 mg/m³ 155 min 4.6 mg/m³ 90 min 2.1 mg/m³ 46 min

Based on this information, determine the employee's actual exposure to iron oxide, whether the samples were valid, and if not, why? Show your work either in the report or as an appendix.