WTC environmental investigation report, Sep 2002

NYC 9/11 Public Portal Document

Final Technical Report of the Public Health Investigation Page 41 of 56 expected from the skin and eye irritation that may have occurred because of exposure to synthetic vitreous fibers.

No adverse pulmonary health effects are expected from the levels of airborne synthetic vitreous fibers measured in this investigation.

The primary short-term and acute health effects of SVF are skin, upper respiratory tract, and eye irritation (42). It is the physical shape and size of the SVF fibers that cause irritation, generally fibers more than 5 microns in diameter cause skin irritation (41,43,44). The affected area may itch and a rash may form. These symptoms subside as exposure is ended, as the fibers slowly work themselves out of the affected tissue. Upper respiratory tract irritation due to inhaled fibers has been reported when fiber concentrations were greater than 1 f/cc in air (41,42,45).

Generally this type of irritation has been observed in individuals who are manufacturing and installing SVF insulation materials. Although the settled surface dust results indicate SVF is present in many areas of lower Manhattan, total dust loading is not known. Because these irritant health effects would be due to the total amount of SVF contact exposure, dust loading as well as activity levels would influence whether a particular environment was irritating. Extremely low levels were detected in the air samples analyzed via SEM. In the PCM analysis, even if all of the fibers counted are assumed to be SVF, the detected maximum value of 0.003 f/cc is well below the documented level of irritation. These data indicate that SVF is present at elevated levels in settled surface dust and may be an irritant under certain conditions, or to sensitive individuals. No long-term health effects are expected from the skin, eye, or upper respiratory tract irritation related to the SVF exposure.

b. Pulmonary Effects

SVF less than 3 microns in diameter are respirable and available to enter and deposit in the pulmonary regions of the lung (41). Clearance of these fibers from the lung will be determined by fiber solubility and length (41,42). Fibers cleared from the lung have less potential to create long-term health effects.* Although some animal studies have demonstrated both fibrotic and carcinogenic potential for fibrous glass and mineral wools (41,42,46), more recent studies do not fully support this finding.^ Epidemiologic studies on workers exposed to fibrous glass do not provide consistent evidence of pulmonary effects, although some effects were noted (42,47). Similarly, when assessing deaths due to lung cancer in workers exposed to glass wool, studies do not provide strong evidence for increased risk of cancer deaths attributable to glass wool fiber exposures.

http://www.atsdr.cdc.gOv/asbestos/lowennanhattan/ResSamp_Sep2002_Text.html 07/18/2003 NYC-WTC_000178428