We would first like to answer this question by restating the information contained within the public notice as provided by the State Health Department.
"The presence of haloacetic acids at the concentrations detected in the water system does not constitute an immediate health hazard. Although the standard is slightly exceeded, it is not a 'bright line' between drinking water concentrations that cause health effects and those that do not. The standard for haloacetic acids is set at a water concentration at which exposure is much lower than exposures identified as causing health effects in animals. Thus, exceedance of the standard is not a trigger for health effects, but a trigger for water suppliers to take action to reduce the haloacetic acid concentrations and maintain what is already a large margin of protection against health effects."
Provided for you on our website is a fact sheet on Haloacetic Acids issued by the New Hampshire Department of Environmental Sciences which summarizes the carcinogenic (cancer producing) effects of the contaminant:
"Human studies have yet to confirm that DCA or TCA [Haloacetic Acids] exposure increases the risk of cancer. Based on the animal data, at the current HAA5 regulatory level [60 micrograms per liter], the cancer risk is estimated to increase by about 1 in 60,000 for every 10 years of exposure."
This cancer risk was estimated by EPA and is based on animal testing data. Animal studies that have shown impacts of Haloacetic Acids occurred with continuous high levels of exposure between 4 and 18 times the standard regulatory amounts.