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WTC OSHA Silica Sampling Data for West Area
Please Note:The PEL for Respirable Dust containing crystalline silica (quartz) is determined individually for each sample, using the following formula:
PEL = 10mg/m3 ÷ (%SiO2+2), where %SiO2 refers to the amount of crystalline silica measured in that sample.
This calculated PEL is compared with the Respirable Dust sample result to determine whether there is an overexposure. According to this formula, if there is no crystalline silica found in a sample, the PEL for that Respirable Dust sample is 5.0 mg/m3. As the formula implies, the PEL for respirable dust containing crystalline silica varies depending on the concentration of crystalline silica in the sample. The higher the concentration of crystalline silica the lower the PEL. (Click here for more information on the crystalline silica and the OSHA PEL.)
The Particulates not otherwise regulated (Respirable Fraction) OSHA permissible exposure limit (PEL) is 5.0 mg/m3.
aOther forms of crystalline silica (cristobalite) have not been detected in WTC samples. bResults are averaged and reported for the time duration stated. cND = Crystalline Silica None Detected.
| Date Taken | Operation | Sample Type | Duration (min) | Respirable Dust TWAb mg/m3 | Crystalline Silicaa (Quartz)c %b | PEL mg/m3 (based on formula) | Respirable Dust TWAb >PEL? |
| 04/20/02 | Area | 365 | 0.110 | 32.00 | 0.294 | ||
| 04/18/02 | Area | 503 | 0.041 | ND | 5.000 | ||
| 04/18/02 | Personal | 320 | 0.079 | ND | 5.000 | ||
| 04/18/02 | Personal | 188 | 0.650 | 39.00 | 0.244 | YES | |
| 04/18/02 | Personal | 455 | 0.420 | 25.00 | 0.370 | YES | |
| 04/15/02 | AREA SAMPLE | Area | 467 | 0.049 | ND | 5.000 | |
| 04/15/02 | AREA SAMPLE | Area | 327 | 0.099 | ND | 5.000 | |
| 04/11/02 | Personal | 457 | 0.340 | ND | 5.000 | ||
| 04/11/02 | Personal | 456 | 0.190 | 14.00 | 0.625 | ||
| 04/11/02 | Personal | 454 | 0.480 | 6.10 | 1.235 | ||
| 04/11/02 | Personal | 487 | 0.320 | 9.10 | 0.901 | ||
| 04/11/02 | Personal | 452 | 0.065 | ND | 5.000 | ||
| 02/24/02 | Personal | 405 | 2.200 | 3.00 | 2.000 | YES | |
| 02/24/02 | Area | 465 | 0.100 | ND | 5.000 | ||
| 02/24/02 | Area | 465 | 0.046 | ND | 5.000 | ||
| 02/24/02 | Area | 460 | 0.000 | ND | 5.000 | ||
| 02/19/02 | LABORER | Personal | 492 | 0.390 | 6.70 | 1.149 | |
| 02/13/02 | Personal | 435 | 0.470 | ND | 5.000 | ||
| 02/11/02 | Personal | 435 | 0.110 | ND | 5.000 | ||
| 02/11/02 | Area | 420 | 0.190 | ND | 5.000 | ||
| 02/10/02 | Personal | 92 | 0.280 | ND | 5.000 | ||
| 02/08/02 | GRAPPLER | Personal | 454 | 0.130 | ND | 5.000 | |
| 01/29/02 | Area | 385 | 0.048 | ND | 5.000 | ||
| 01/21/02 | AREA SAMPLE | Area | 480 | 0.120 | ND | 5.000 | |
| 01/21/02 | DRILLER | Personal | 385 | 0.160 | ND | 5.000 | |
| 01/19/02 | Area | 430 | 0.000 | ND | 5.000 | ||
| 01/17/02 | Personal | 447 | 0.230 | ND | 5.000 | ||
| 01/17/02 | Personal | 451 | 0.210 | ND | 5.000 | ||
| 01/17/02 | Area | 410 | 0.063 | 57.00 | 0.169 | ||
| 01/17/02 | Area | 388 | 0.055 | ND | 5.000 | ||
| 01/17/02 | Area | 361 | 0.130 | ND | 5.000 | ||
| 01/16/02 | Area | 270 | 0.055 | ND | 5.000 | ||
| 01/11/02 | Area | 305 | 0.083 | ND | 5.000 | ||
| 01/11/02 | Area | 310 | 0.160 | 28.00 | 0.333 | ||
| 01/11/02 | Area | 285 | 0.130 | ND | 5.000 | ||
| 01/11/02 | Personal | 90 | 0.150 | ND | 5.000 | ||
| 01/09/02 | LABORER | Personal | 377 | 0.018 | ND | 5.000 | |
| 01/05/02 | AREA SAMPLE | Area | 375 | 0.160 | ND | 5.000 | |
| 01/04/02 | AREA SAMPLE | Area | 305 | 0.130 | ND | 5.000 | |
| 01/04/02 | AREA SAMPLE | Area | 305 | 0.079 | ND | 5.000 | |
| 01/04/02 | AREA SAMPLE | Area | 383 | 0.160 | 12.00 | 0.714 | |
| 01/04/02 | AREA SAMPLE | Area | 400 | 0.180 | ND | 5.000 | |
| 01/04/02 | DOCKBUILDER | Area | 180 | 0.470 | 14.00 | 0.625 | |
| 01/03/02 | DOCKBUILDER | Personal | 143 | 1.800 | 3.80 | 1.724 | YES |
| 01/03/02 | AREA SAMPLE | Personal | 154 | 0.120 | ND | 5.000 | |
| 01/03/02 | Personal | 362 | 0.094 | ND | 5.000 | ||
| 01/03/02 | Personal | 375 | 0.099 | ND | 5.000 | ||
| 01/03/02 | Area | 240 | 0.061 | ND | 5.000 | ||
| 01/03/02 | Area | 415 | 0.110 | ND | 5.000 | ||
| 01/03/02 | GRAPPLER/CLAW OPERATOR/OPERATING ENGINEER | Personal | 410 | 0.160 | ND | 5.000 | |
| 01/03/02 | Area | 300 | 0.000 | ND | 5.000 | ||
| 01/02/02 | Personal | 205 | 0.000 | ND | 5.000 | ||
| 01/02/02 | Personal | 172 | 0.990 | 15.00 | 0.588 | YES | |
| 01/02/02 | Personal | 420 | 0.240 | ND | 5.000 | ||
| 01/01/02 | Personal | 350 | 0.068 | ND | 5.000 | ||
| 01/01/02 | Personal | 318 | 0.100 | ND | 5.000 | ||
| 01/01/02 | Personal | 344 | 0.044 | ND | 5.000 | ||
| 01/01/02 | Personal | 458 | 0.077 | ND | 5.000 | ||
| 12/29/01 | AREA SAMPLE | Area | 405 | 0.074 | ND | 5.000 | |
| 12/27/01 | Area | 408 | 0.026 | ND | 5.000 | ||
| 12/26/01 | Area | 423 | 0.100 | ND | 5.000 | ||
| 12/26/01 | Personal | 422 | 0.130 | ND | 5.000 | ||
| 12/20/01 | GRAPPLER | Personal | 410 | 0.047 | ND | 5.000 | |
| 12/20/01 | GRAPPLER | Personal | 380 | 0.043 | ND | 5.000 | |
| 12/20/01 | GRAPPLER | Personal | 400 | 0.043 | ND | 5.000 | |
| 12/20/01 | LABORER | Personal | 423 | 0.015 | ND | 5.000 | |
| 12/19/01 | Personal | 359 | 0.130 | 26.00 | 0.357 | ||
| 12/19/01 | Area | 420 | 0.240 | ND | 5.000 | ||
| 12/19/01 | Area | 545 | 0.120 | ND | 5.000 | ||
| 12/19/01 | Area | 429 | 0.180 | ND | 5.000 | ||
| 12/19/01 | Personal | 359 | 0.078 | ND | 5.000 | ||
| 12/19/01 | Area | 391 | 0.029 | ND | 5.000 | ||
| 12/18/01 | Area | 377 | 0.032 | ND | 5.000 | ||
| 12/18/01 | Personal | 359 | 0.050 | ND | 5.000 | ||
| 12/18/01 | Area | 384 | 0.200 | ND | 5.000 | ||
| 12/18/01 | Area | 395 | 0.230 | ND | 5.000 | ||
| 12/14/01 | DOCKBUILDER | Personal | 198 | 0.180 | 21.00 | 0.435 | |
| 12/10/01 | Personal | 456 | 0.072 | 26.00 | 0.357 | ||
| 12/04/01 | Personal | 320 | 3.900 | ND | 5.000 | ||
| 12/04/01 | Personal | 175 | 0.061 | ND | 5.000 | ||
| 12/04/01 | Area | 310 | 0.130 | ND | 5.000 | ||
| 12/01/01 | AREA SAMPLE | Area | 280 | 0.034 | ND | 5.000 | |
| 12/01/01 | AREA SAMPLE | Area | 290 | 0.029 | ND | 5.000 | |
| 11/28/01 | AREA SAMPLE | Area | 365 | 0.110 | ND | 5.000 | |
| 11/25/01 | Area | 330 | 0.046 | ND | 5.000 | ||
| 11/23/01 | Area | 440 | 0.046 | ND | 5.000 | ||
| 11/19/01 | AREA | Area | 360 | 0.200 | 10.00 | 0.833 | |
| 11/18/01 | GRAPPLER/CLAW OPERATOR/OPERATING ENGINEER | Personal | 337 | 0.110 | ND | 5.000 | |
| 11/18/01 | GRAPPLER/CLAW OPERATOR/OPERATING ENGINEER | Personal | 327 | 0.290 | ND | 5.000 | |
| 11/17/01 | AREA SAMPLE | Area | 221 | 0.061 | ND | 5.000 | |
| 11/17/01 | AREA SAMPLE | Area | 67 | 0.035 | ND | 5.000 | |
| 11/16/01 | CRANE OPERATOR | Personal | 358 | 0.160 | ND | 5.000 | |
| 11/14/01 | OPERATING ENGINEER | Personal | 305 | 0.066 | ND | 5.000 | |
| 11/13/01 | IRONWORKER/TORCH CUTTER | Personal | 370 | 0.830 | ND | 5.000 | |
| 11/13/01 | Area | 345 | 0.720 | ND | 5.000 | ||
| 11/04/01 | LABORER | Personal | 405 | 1.100 | ND | 5.000 | |
| 10/30/01 | LABORER | Personal | 292 | 0.061 | ND | 5.000 | |
| 10/30/01 | EXCAVATING ENGINEER | Personal | 344 | 0.190 | ND | 5.000 | |
| 10/29/01 | CRANE OPERATOR | Personal | 212 | 0.044 | ND | 5.000 | |
| 10/27/01 | EXCAVATOR OPERATOR | Personal | 386 | 0.210 | ND | 5.000 | |
| 10/27/01 | EXCAVATOR OPERATOR | Personal | 372 | 0.140 | ND | 5.000 | |
| 10/23/01 | GRAPPLER OPERATOR | Personal | 378 | 0.033 | ND | 5.000 | |
| 10/23/01 | GRAPPLER OPERATOR | Personal | 430 | 0.120 | ND | 5.000 | |
| 10/23/01 | WATER TRUCK OPERATOR/GENERAL LABORER | Personal | 335 | 0.100 | ND | 5.000 | |
| 10/22/01 | GRAPPLER/CLAW OPERATOR/OPERATING ENGINEER | Personal | 405 | 0.150 | ND | 5.000 | |
| 10/21/01 | Area | 407 | 0.051 | ND | 5.000 | ||
| 10/19/01 | TORCH CUTTING STEEL BEAMS WEST AREA OF PILE WTC-1 | Personal | 412 | 0.320 | ND | 5.000 | |
| 10/18/01 | TORCH CUTTER/BURNING | Personal | 384 | 0.044 | ND | 5.000 | |
| 10/15/01 | Area | 240 | 2.300 | ND | 5.000 | ||
| 10/13/01 | Area | 420 | 0.000 | ND | 5.000 | ||
| 10/11/01 | CRANE OPERATOR/OPERATING ENGINEER | Personal | 320 | 0.020 | ND | 5.000 | |
| 10/11/01 | CRANE OPERATOR/OPERATING ENGINEER | Personal | 300 | 0.200 | ND | 5.000 | |
| 10/11/01 | Area | 420 | 0.000 | ND | 5.000 | ||
| 10/10/01 | GENERAL LABORER/SPOTTER | Personal | 278 | 0.120 | ND | 5.000 | |
| 10/10/01 | IRONWORKER-BURNER/CUTTER | Personal | 281 | 1.500 | ND | 5.000 | |
| 10/09/01 | IRONWORKER-BURNER/CUTTER | Personal | 365 | 0.830 | ND | 5.000 | |
| 10/09/01 | CRANE OPERATOR/OPERATING ENGINEER | Personal | 328 | 0.170 | ND | 5.000 | |
| 10/08/01 | Area | 287 | 0.110 | ND | 5.000 | ||
| 10/06/01 | Area | 309 | 0.310 | ND | 5.000 | ||
| 10/05/01 | Area | 243 | 0.190 | ND | 5.000 | ||
| 10/04/01 | Area | 466 | 0.470 | ND | 5.000 | ||
| 10/03/01 | GRAPPLER/CLAW OPERATOR/OPERATING ENGINEER | Personal | 154 | 0.210 | ND | 5.000 | |
| 10/01/01 | LABORER-CLEAN UP | Personal | 380 | 0.720 | ND | 5.000 | |
| 09/29/01 | GRABBER/CLAW OPERATOR/OPERATING ENGINEER | Personal | 310 | 0.018 | ND | 5.000 | |
| 09/29/01 | CRANE OPERATOR/OPERATING ENGINEER | Personal | 250 | 0.022 | ND | 5.000 | |
| 09/29/01 | IRONWORKER-BURNER/CUTTER | Personal | 385 | 0.990 | ND | 5.000 | |
| 09/28/01 | IRONWORKER-BURNER/CUTTER | Personal | 235 | 0.480 | 42.00 | 0.227 | YES |
| 09/28/01 | CRANE OPERATOR/OPERATING ENGINEER | Personal | 283 | 0.030 | ND | 5.000 | |
| 09/27/01 | BOBCAT OPERATOR | Personal | 345 | 0.044 | ND | 5.000 | |
| 09/27/01 | LABORER | Personal | 234 | 0.240 | ND | 5.000 | |
| 09/26/01 | IRONWORKER-BURNER/CUTTER | Personal | 270 | 0.970 | ND | 5.000 | |
| 09/25/01 | Area | 235 | 0.022 | ND | 5.000 | ||
| 09/24/01 | LABORER-CLEAN UP | Personal | 240 | 1.200 | 2.00 | 2.500 | |
| 09/24/01 | CRANE OPERATOR | Personal | 180 | 0.000 | ND | 5.000 | |
| 09/24/01 | LABORER | Personal | 297 | 0.083 | ND | 5.000 | |
| 09/24/01 | Area | 240 | 0.140 | ND | 5.000 | ||
| 09/23/01 | Area | 219 | 0.130 | ND | 5.000 | ||
| 09/17/01 | Area | 247 | 0.000 | ND | 5.000 |