NYC-WTC_000232340

NYC 9/11 Public Portal Document

Liberty Mutual / ATC Measurement Data

Weekly Summary

# o1 a of Highest Highest OSHA ACGIH Highest Result Job with Highest #ofNQs %NQ Comments Week of: Aqent Class Samples Analyses Analyte Result PEL TLV % of OEL Exposure

11/25/01 Total Dust/Metals 17 340 Cadmium 2.8 ug/m3 5 ug/m3 10 ug/m3 56% of PEL Torch Cutter 198 58% 11/25/01 Resp. Dust'Silica 13 39 Quartz 0.018 mg/m3 0.1 mg/m3’ 0.05 mg/m3 36% of TLV Spotter 27 69% 11/25/01 Aromatics 28 Toluene 0.0038 ppm 200 ppm 50 ppm 0.0076% of TLV Torch Cutter 26 93% 11/25/01 Aldehydes 3 21 Formaldehyde 0.010 ppm 0.75 ppm 0.3 ppm (Ceiling) 1.3% of PEL Backhoe Operator 15 71% 11/25/01 PAHs 6 96 Total PAHs 6.8 ug/m3 200 ug/m3 200 ug/m3 3.4% of PEL Grappler Operator 75 78% 11/25/01 Asbestos 24 24 Fibers 0.033 f/CC 0.1 f/cc 0.1 f/cc 33% Of PEL Spotter 4 17% 11/25/01 Acids 6 36 Hydrofluoric Acid 0.01 ppm 3 ppm 3 ppm (Ceiling) 0.33% of TLV Grappler Operator 59 164% 11/25/01 Ozone 2 2 N/A All "Too Low to Quantify" 2 100% 11/25/01 Carbon Monoxide (TWA) 26 26 Carbon Monoxide 33 ppm 50 ppm 25 ppm 132% of TLV (abbreviated Flagman 15 58% 1 peak over NIQSH Ceiling of 200 sample - 2 hrs, 9 min) ppm (Grappler Operator)

Totals: 104 612

12/1/01 Total Dust/Metals 10 202 Arseric 1 ug/ni3 10 ug/m3 10 ug/m3 10% of PEL Torch Cutter 122 60% 12/1/01 Resp. Dust'Silica 8 24 Respirable Dust 0.34 mg/m3 5 mg/m3 3 mg/m3 11% of TLV Equipment Operator 19 79% 12/1/01 Aromatics 12 48 Benzene 0.0032 ppm 1 ppm 0.5 ppm 0.64% of TLV Equipment Operator 31 65% 12/1/01 Aldehydes 6 42 Formaldehyde 0.017 ppm 0.75 ppm 0.3 ppm (Ceiling) 2.3% of PEL Equipment Operator 29 69% 12/1/01 PAHs 6 96 Total PAHs 17 ug/m3 200 Ljg/m3 200 ug/m3 8.5% of PEL Torch Cutter 52 54% 12/1/01 Asbestos 26 26 Fibers 0.048 0.1 f/cc 0.1 f/cc 48% Of PEL Spotter 5 19% 12/1/01 Acids 6 36 Sulfuric Acid 0.059 mg/m3 1 mg/m3 1 mg/m3 5.9% of PEL Grappler Operator 31 86% 12/1/01 Ozone 8 8 N/A All "Too Low to Quantify" 8 100% 12/1/01 Carbon Monoxide (TWA) 18 18 Carbon Monoxide 5 ppm 50 ppm 25 ppm 20% of TLV Torch Cutter 14 78%

12/1/01 Hydrogen SiJfide 8 8 Hydrogen Sulfide 16 ppm 20 ppm (Ceiling) 10 ppm 160% of TLV (Area Sample) SW Corner, near south bridge 5 63% 12/1/01 Diesel Fume 11 Inorgaric Carbon 0.075 mg/m3 3.5 mg/m3 3.5 mg/m3 2.2% of PEL Torch Cutter 1 9% Totals: 108 508

Notes:

The PEL for quartz is determined by the formula PEL = 10 mg/m3 /(% quartz -1-2). For dusts with high quartz content this works out to be a quartz concentration of approximately 0.1 mg/m3.

"OEL" = "occupational exposure limit". A genetic term encompassing PELs, TLVs and otherwotkplace exposure limits.

"NQ" = "not quantifiable". Substance was was not present insufficient quantity in the sample to report a firm value for the concentration. All quantification levels for the sampling methods used are well below occupational exposure limits.

The area samples for hydrogen sulfide were taken near suspected sources and were not representative of worker exposure.

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NYC-WTC_000232340