NYC-WTC_000233682

NYC 9/11 Public Portal Document

response guidelines

Consult with public health • Estimate affected area and isolate • Characterize affected area. agency and primacy agency. if possible. • Revise public health protection 1 Consult external information • Implement appropriate public measures as necessary. sources. health protection measures. • Provide alternate water supply. s • Plan for alternate water supply. • Plan remediation activities. p • Identify sites and initiate site o characterization. • Analyze samples. s

Notification from public health officials regarding a potential water contamination incident is unique in that individuals have been exposed to a harmful substance resulting in illness, disease or death in the population. The threat evaluation in this case may be part of a larger epidemiological investigation to determine the cause of disease. It is critical that the utility work with the appropriate public health officials from the outset, since these officials will likely have information critical for the evaluation. For example, they may know or suspect the causative agent based on clinical information. This knowledge, in conjunction with information about the properties of the contaminant, may indicate whether or not contaminated water is even a possibility. For example, if the causative agent is known to immediately break down into harmless byproducts upon exposure to water, then the possibility of contaminated water might be dismissed.

If water is considered a possible carrier for the contaminant, then further investigation should be conducted to determine if water is the most likely carrier of the contaminant (i.e., analogous to the ‘credible’ stage of the threat evaluation). Information that may help to make this determination will include additional findings from the larger epidemiological investigation, geographic distribution of exposure, recent water quality and operational data, and reports of consumer complaints. If this additional information indicates that water contamination is likely, response actions would likely include public notification and sampling for the contaminant. The sampling plan developed at this point may start with information about the geographic distribution of exposure; however, consideration must be given to the latency period of the disease, which could be from minutes to weeks, as well as the travel time within the system. The objectives of sampling and analysis at this point would include: 1) confirming the presence of the contaminant in the water; 2) determining if the contaminant is still present; and 3) determining the area affected. If water contamination is confirmed, and the contaminant is still present in the system, it will be necessary to begin planning for remediation and recovery efforts. If the contaminant is not found, extensive sampling would likely be necessary to demonstrate that the contaminant is indeed absent from the system.

78 Interim Final - August 2004

CITY_21MC100_004992417

NYC-WTC_000233760