NYC 9/11 Public Portal Document
Bespirable Silica: The overwhelming majority 861 silica samples (excluding l>vlk and bliuik s’
samples} show no detectable levels of aiibome silica. However, 54 exposucres'
exceeded the PEL. The hipest sample result was approximatiriy twenty-one
times the OSHA limit (jack hammmuig concrete 16 feet below grade). The
other elevated exposures were approximately one to founeen tunes the OSHA
limit. These cs^oeurae ocenrred during: 1) pre-drilling /sluny wall 2) jack
haaunsring, rubble removal and loading operations near the "Winter Garden;
4) during the breaking up of concrete in the pit; 5) while drillmig ths concrete
slutty wall, 6) flagging operations in pit, and 7) adtile chippies concrete with
power tools during donolition activities at ? WTC’s parking garage. Moat of
the work areas where apparent overexposures lo silica occurred were in the
rubble pfle/^nt; an area where OSHA continuec to tocomnge the use ctT
respiratory protectioa.
Organic
Compoumis: OSHA has taken a total of 652 samples (excluding bulk and blank samples)
for organic compounds such as acetaldehyde, acrolein, acryioaitxilc, benzene,
2-butanone, carbofiifans, dioxin, PCBs, eth>d benzene, formaldehyde. Freon
R-22 (chlorodiflouromefhane), hexone, isocyanates (e.g. MDl TOI),
perchloroEthylene, polynuclear aromatics, phosgene, styrene, toluene, 1-3
butadiene, trichlorodhyiene, vinyl chloride, glutaraldehydfi, and xjdeae.
Screening samples initially showed elevated levels of some organic chemicals
resulting from the fixes burning in the rubble pile. Subsequent personal and
area somplex show weaker exposure levels to be below OSHA limits.
However, one personal sample result for a benzene sample taken was found to
be at the 8-hr. OSHA Allowable Limit cooceafration of 1 ppm. This was found
on a backhoe operator moving debris on lQ/7/01. See infonnatiaa below for
the specific counts in regards to polynuclear aromatics. Freon R-22, phoegeoe
and dioxin.
Dioxins: OSKA has taken 10 dioxin samples (axclodiag blanks) in deplume over hot
spots in (and around the perimeter of) the nibble pile. Dioxi* levels detected
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