Draft asbestos criteria discussion memo, January 2002

NYC 9/11 Public Portal Document

Draft for Discussion-

The World Trade Center disaster and the potential for the release of asbestos fibers from rescue activities, fire fighting, and removal and clearance of debris at the site resulted in a number of different agencies establishing monitoring networks to monitor for airborne asbestos. These monitors served a number of purposes. The measured concentrations were used to protect emergency personnel working at the site, serving to define where breathing masks were required, as well as a check on the control measures that were put in place to minimize asbestos from becoming airborne from the activities in and around the site. The monitors also served the purpose of assuring the general public who worked or lived near the site that they were not being exposed to excessive levels of asbestos. (Separate short term efforts to assure that buildings near ground zero had been successfiilly cleaned, as well as a study of indoor exposures near and at a distance from ground zero were also done, but are not the subject of this discussion.)The monitoring effort was later expanded to include some schools in the area, to assure the parents and teachers that there was no threat from ambient levels of asbestos. Monitoring efforts also included sites further from ground zero to assure the general public that they were not at risk from exposure to ambient levels of asbestos.

The above asbestos monitoring efforts resulted m a dense monitoring network in and around the World Trade Center. In some cases, the monitoring sites established by an agency were either very close to one another or very close to monitors that were setup by other agencies. The sampling times, used by various agencies, however, was not necessarily the same. The proximity of the various monitors was not felt to be a problem, in the early stages of monitoring, as readings from adjacent monitoring sites could be used to confirm high observations. The cleanup of the World Trade Center site has progressed to a point where it is now felt that more than half the cleanup has been completed. This includes most or all of the major demolition that was needed-(to be checked). The cleanup should be completed by about June 2002. The progress made in the removal of material from the site, and the effectiveness of controls put in place to minimize airbome emissions have been confirmed by the feet that ambient asbestos measurements have essentially have dropped below levels of concern. Therefore, this would appear to be an appropriate time to review the monitoring effort for asbestos and determine what level of effort is appropriate for the remainder of the cleanup.

The revamping of the asbestos monitoring effort should reflect the reduced potential for airborne emissions, the changes in the active work site, the trend in measured ambient levels at the various monitors, and the proximity of other monitoring locations. The aim of the revamping of the networks should be to eliminate unnecessary, or duplicative monitoring sites, while preserving an adequate network to assure the continued adherence by site workers to work practices that will minimize potential air emissions and assure the safety of the general public. Currently, the EPA has ~19 fixed monitoring sites in and around the World Trade Center site and the NYCDEP ~20 fixed monitoring sites. (This does not include monitoring sites specifically setup in front of schools.- DEP 4 sites? EPA? Anyone else? ) The NYSDEC has seven monitoring sites where asbestos is also done. Two of the sites are near die WTC on colleges, and five are removed from the site, with four in other Boroughs.

The criteria that I recommend for examining which sites are candidates for removal in the second phase of World Trade Center cleanup are:

1) Sites with no observations above the AHERA standards for the last two months- through 1/15/02- a) There is an exception to the above. If any site has a reading above the AHERA standard that was the result of a major demolition, this should not be considered when determining observations above die AHERA standards for the two last months.

2) Sites within 200’ of another monitoring site.

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