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The debate over whether to tighten the drinking water standard for arsenic highlighted a key problem with federal drinking water regulation: the inappropriateness of the federal government’s setting local priorities. At any time, local governments and utilities can monitor and control any contaminant they choose, and they know better where to devote their scarce resources. Nonetheless, as the case of arsenic demonstrates, the Safe Drinking Water Act (SDWA) allows federal regulators to impose priorities even when they promise a net loss to public health and well-being. 

Arsenic is an element that is a natural part of Earth’s crust. It exists in organic and inorganic forms, but the U.S. Environmental Protection Agency (EPA) regulations focus on inorganic arsenic because it is more prevalent in drinking water. Traditionally, many critics have contended that inorganic arsenic was the principal danger to public health. But the EPA Science Advisory Board (SAB) pointed out that the research is actually far less clear. Recent research indicates that at least some forms of organic arsenic are carcinogenic, and some may be more toxic than inorganic forms. 

The drinking water standard for most regulated substances is specified as a “maximum contaminant level,” or MCL. The MCL sets the maximum amount of a substance that the EPA will allow in tap water. Between 1975 and 2002, the EPA used an MCL of 50 parts per billion for arsenic, which meant that it allowed no more than 50 parts per billion of arsenic per liter of tap water. This standard was set as an “interim standard” after the passage of the SDWA. The 1986 revisions to the law mandated that the agency set a final standard by 1989. 

After the agency missed the legislative deadline and a court-ordered deadline, amendments to the SDWA in 1996 extended the deadlines for the rule. The amendments required the agency to propose a standard by January 2000 and to finalize the rule by January 2001. In June 2000—five months later than legislatively mandated— the agency proposed a new standard of five parts per billion. Because EPA proposed rule late, lawmakers, water providers, and local officials expressed concern that there was not enough time to consider fully the proposed rule and its implications. Congress responded by including language in a fiscal year 2000 appropriations bill that extended the deadline for six additional months. 

But in the waning days of the Clinton administration, the EPA published a final standard of 10 parts per billion in the Federal Register. The standard would have been effective starting March 23, 2001, although water systems would have had until 2006 to comply. Senator Pete Domenici (R-NM) responded by introducing S. 223, which would void the new rule. In March 2001, the Bush administration announced that it would delay the effective date of the standard for 60 days to review the rule and the underlying science. In April 2001, the administration issued a notice announcing that it would delay the final rule until 2002, after further scientific review and a cost analysis were complete.4 The delay of the rule proved controversial, as the Democratic National Committee and environmental activists suggested that the delay would threaten public health. The administration completed its review and issued the Clinton standard in the fall of 2001.