The EPA conducted extensive review of scientific data related to the health effects of exposure to perchlorate from drinking water and other sources and found that in more than 99 percent of public drinking water systems, perchlorate was not at levels of public health concern. Therefore, based on the Safe Water Drinking Act criteria, the agency determined there is not a "meaningful opportunity for health risk reduction" through a national drinking water regulation.
The agency is seeking comment on its preliminary determination not to regulate perchlorate in drinking water at a national level. EPA will make a final determination for perchlorate after considering information provided in the 30-day public comment period.
While fewer than one percent of the drinking water sources have perchlorate levels above the health reference level, EPA is committed to working with states and localities to ensure public health is protected. States have the right to establish and enforce drinking water standards and EPA encourages state-specific situations to be addressed at the local level. EPA intends to issue a health advisory at the time it issues its final regulatory determination for perchlorate, to assist states with their local response.
A regulatory determination is a formal decision by EPA as to whether it should initiate development of a national primary drinking water regulation for a specific contaminant under the Safe Drinking Water Act. EPA has drinking water regulations for more than 90 contaminants. Every five years, EPA develops a Contaminant Candidate List of contaminants to consider for regulation and then makes regulatory determinations on some of the contaminants based on scientific information on health effects, occurrence in drinking water and the opportunity for risk reduction.
A health advisory provides technical guidance to federal, state, and other public health officials on health effects, analytical methods and treatment technologies associated with drinking water contamination. Health advisories also contain guidance values that are concentrations of a contaminant in drinking water that are likely to be without adverse health effects.
Information on Drinking Water Regulatory Determinations: http://www.epa.gov/safewater/ccl/reg_determine2.html
Click on Title link for more information. Source: EPA Water Headlines