DEP memo on vehicle release from Ground Zero, January 24,

NYC 9/11 Public Portal Document 1-24-02:12:30PM;NYC Law Department 21236,0765 # ,9/ 55 J HN-dei-tfiaad ustr unii kh. H. Ibzqj

Industrial Hygiene Survey Federal Bureau of Investigation, Staten Island, NY

Nickel 1 mg/M3 <0.0004 mg?M3 Thallium O.l mgZM3 <0.0002 nig/M3 Vanadium 0.5 mg/M3 <0.001 mg/M3 Zinc 5 mg/M3 <0.003 mg/M3

Levels of each of the metals scanned were well below the OSHA permissible exposure limits. Because of the extremely low levels of metals detected in the samples, testing for metals was discontinued and in subsequent testing only lead was tested for.

Seven personal exposure samples were collected on s^^^ays in October and analyzed for lead. Page 7 of the attached analytical report summarizes the lead in air sample reports. The results are reported in milligrams per filter. Each sample volume typically ranged from 500 to 700 liters ♦ (0.5 to 0.7 M’). Six of the samples were found to have no delectable lead (<0.002 mg/M^). One personal sample for lead had 0.002 mg/M\ These were well below the PEL of 0.05 mg/M^. Additional sampling for metals has not been conducted since October 31,2001,

Total Dust Page 34 of the attached analytical data table summarizes the total dust in air samples. The results are reported in total milligrams per filter. The volume collected for each sample ranged from 500 to 700 liters Six personal samples were collected for total dust levels. The OSHA permissible exposure limit for total dust is 15 mg/M\ The highest level detected was 1.03 mg/m\

Silica Dust Eleven personal samples were collected and analyzed for respirable dust. The results are summarized in the analytical results provided in the appendix. The results are reported in total milligrams per filter and milligrams of Quartz, cristobalite, and tridymite. Four area samples were collected in the debris field and analyzed for respirable dust These are reported as ambient in the attached analytical data report. The levels of respirable dust on the area samples were all below the detection limit of 0.01 mg/Nzf. A total of thirteen respirable dust samples were taken on Federal law enforcement personnel while raking debris in the open field. The following summarizes the personal sample results:

1. There was no detectable respirable dust on four of the personal samples. 2. On the nine other samples the levels ranged from 0.1 to 0.51 mg/M\ The amount of quartz, cristobalite, and Tridymite were measured in a most of these samples. Cristobalite and tridymite were not detected in any of the samples. Quartz was detected in only one sample. It was found to be at a level of 0.056 mg/M3 and represented 11 % of the sample. The OSHA PEL in this case was 0.77 mg/M3, The level of quartz was well below the OSHA PEL.

Because of the low levels detected on the personal samples, respirable dust exposure monitoring was discontinued after October 31,2001.

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