Chain of Custody Form Instructions for WTC Building Sampling

NYC 9/11 Public Portal Document

Data will be evaluated by local, state and federal public health agencies. Evaluations will include: 1) Indoor sample results will be compared to the results found in the background homes and evaluated on a residence-by- residence basis (for the individual occupants) 2) All indoor data will be compared to the results found in the background homes and evaluated to determine any public health implications for residents near the WTC 3) All outdoor data will be compared to the results found in the backgroimd homes and evaluated to determine any public health implications for those living near the WTC 4) The relationship between materials found in indoor and outdoor samples will be evaluated. For 1 through 3, above, sample results will first be compared to the results from background homes. If results are less than or within the levels found in background locations, then the health interpretation will stress that there is no indication that the resident(s) in the area tested are at any increased risk compared to those in communities further away from the WTC. If sample results are higher than those of the background homes, the results will be compared to screening guidelines. These screening levels are outlined in the next Section. If values are below screening guidelines, the health interpretation will stress that the levels of contaminants found are below those of public health concern. If values exceed the screening guidelines, then sample collection information (Appendix A) will be reviewed in detail to determine if a possible source or contributing source (e.g., remodeling activities, road construction) of the contaminant(s) is possible. If a possible source or contributing source is found, this information will be included in the interpretation of the results. If the possible source is controllable (e.g., sweeping with a broom), recommendations will be made that will reduce levels of contaminants. If no other source of the contaminant(s) is indicated and sample collection information indicates the presence of variables associated with WTC-related dust (e.g., visible settled dust, windows open during WTC collapse), this information will be included in the interpretation of the results. Recommendations to clean (or re-clean) areas to reduce exposures will be made. A public health implications statement will be provided with each set of results. If levels of contaminants are found outdoors that exceed those of the background homes and the screening guidelines, recommendations will be made to take steps that eliminate transporting the contaminants indoors (e.g., reduce contaminant track in by removing or changing shoes prior to entering residence, use higher efficiency filters on HVAC systems, keep windows closed). In addition, a public health implications statement will be provided for outdoor results.

9

NYC-WTC_000149622