Court decision is victory for chlorine, public health

Published May 1, 2000

On March 31, the United States Court of Appeals for the District of Columbia Circuit ruled that EPA violated the Safe Drinking Water Act by failing to use the “best available peer-reviewed science” when it tried to institute a “zero tolerance” standard for chloroform, a byproduct of drinking water disinfection.

Had EPA’s decision been allowed to stand, the use of chlorine to disinfect drinking water would have been effectively banned, with severe public health consequences. Some 98 percent of drinking water in the U.S. is disinfected with chlorine. Health professionals believe alternatives to chlorine, such as treatment with ozone, are less effective and produce their own possibly harmful byproducts.

The Court’s decision reads, “Finding the Agency’s December 1998 rule adopting a zero MCLG [Maximum Contaminant Level Goal] for chloroform to be arbitrary and capricious and in excess of statutory authority, we vacate the rule. . . . In promulgating a zero MCLG for chloroform, EPA openly overrode the ‘best available’ scientific evidence, which suggested that chloroform is a threshold carcinogen.”

Since EPA first proposed the zero MCLG in 1994, dozens of toxicological studies have been published establishing no apparent health effects from exposure to low levels of chloroform. This new information prompted EPA in March 1998 to consider a MCLG of 300 parts per billion (ppb), but intense lobbying by environmental groups led it to remain committed to the zero MCLG, leading to a lawsuit filed by the Chlorine Chemistry Council on behalf of chlorine manufacturers and users.

The Court’s decision can be read at: