Is Our Drinking Water Safe? The EPA’s Decision to Not Limit or Monitor Levels of Toxic Pesticide and Industrial Waste in Our Drinking Water

The fourth Contaminant Candidate List (CCL 4) was published by the Environmental Protection Agency (EPA) on November 17. The Safe Drinking Water Act of 1996 (SDWA) requires the publication of the CCL every five years. The CCL includes contaminants that are not currently governed by the EPA’s Primary Drinking Water Regulations, which place legal limits on the levels of hazardous and carcinogenic contaminants in drinking water.

Every five years the EPA must make a determination whether or not to regulate at least five contaminants from the CCL. Inclusion on the CCL does not necessarily mean a contaminant will be regulated. For example, in 2008, the EPA issued a preliminary decision to not regulate percholate, which has been found in drinking water in the United States. Percholate, which is used by the defense industry as an ingredient in rocket fuel, was first identified as a possible contaminant in 1998. It has been identified with increased risk of neurodevelopmental impairment in fetuses. It has also been linked with delayed development and decreased learning capability in the infants and children of pregnant and lactating women. In February 2011, percholate became the first contaminant to be regulated under the SDWA, when the EPA reversed its preliminary decision.

According to a 2011 US Government Accountability Office (GAO) report, the EPA “based most of its final determinations to not regulate 20 contaminants on the rationale of little to no occurrence of the contaminants in public water systems.” According to an official quoted in the report “in most cases, the agency lacks adequate data to fully characterize the extent of exposure,” and instead, uses a conservative assumption that the relative exposure from drinking water is only 20 percent. This means the EPA simply assumes that 80 percent of our exposure to these contaminants comes from sources other than drinking water, such as inhalation, because it does not have data which prove otherwise. Determinations to not regulate contaminants are based on this assumption.

The report also questioned the credibility of the EPA’s analytical methods in making regulatory determinations, stating that “(The) EPA made decisions on nine contaminants relying on tests that were not sensitive enough to detect them at the agency’s health risk benchmarks.” The GAO found that for 9 of 20 contaminants cleared by the EPA, the lowest level of a contaminant reported under their testing protocols exceeded the health reference level. In other words, the EPA’s testing protocols were not sensitive enough to detect contaminants that posed a health risk. This is terrifying.

Aldrin, Terbufos and Hexachlorobutadiene are among the contaminants the EPA has cleared. Aldrin is a highly toxic insecticide that has been banned by the US Department of Agriculture since 1970. Hexachlorobutadiene is used in the manufacture of rubber compounds. According to the National Institute For Health Open Chemistry Database, “no information is available on the health effects of (this contaminant) in humans.¨ Although the EPA has classified hexachlorobutadiene as a possible human carcinogen, the agency has decided to not limit the levels of this hazardous industrial waste in our drinking water.

In 2011, the EPA decided to not regulate terbufos. Terbufos is another highly toxic pesticide. Earthjustice, a nonprofit public interest law firm, has been fighting for years to convince the EPA to ban Terbufos. The EPA has classified Terbufos as non-carcinogenic to humans, but a 2010 study has found “suggestive associations” between occupational Terbufos use and several forms of cancer. The authors of the study caution there simply is not enough existing experimental evidence to support a stronger link between Terbufos exposure and cancer. Despite lack of evidence that they are safe, the EPA continues to clear these contaminants. There are no regulations in place to limit, or even monitor, the levels of these widely used industrial and agricultural contaminants in our drinking water.

Contaminants that are currently on the list of unregulated contaminants include RDX, an explosive used by the US military in thousands of munitions that is classified by the EPA as a possible human carcinogen; methyl bromide, a highly toxic pesticide linked with depletion of the ozone layer; Methyl Tertiary Butyl Ether (MTBE), a carcinogenic gasoline additive that has been detected in drinking water throughout the United States; Tribufos, a carcinogenic and highly toxic pesticide; Ethoprop, a carcinogenic and highly toxic pesticide; Dimethipin, a Class C possible carcinogen and toxic pesticide; o-Toludine, a carcinogen used primarily in dye manufacturing.

RDX, methyl bromide and MTBE were not included on the list of contaminants to be monitored for possible regulation over the next five years.