I-TEAM: Cancer-causing chemical in local water supply

Posted at 10:35 PM, Sep 14, 2017
and last updated 2017-09-15 00:02:00-04

You've probably never heard of it, but there's a chemical called 1,4 Dioxane that could be in your water supply. And it can come from items you have in your home.

Every five years, the Environmental Protection Agency has local water sources tested for chemicals. Sometimes nothing comes up in the UCMR tests, but in the last test the Village of Grafton showed evidence of a cancer-causing contaminant. 

A group called the Environmental Working Group gathered all the numbers on water testing and found Grafton has almost twice the safe amount of 1,4 Dioxane in it's tap water. 

"This well will actually put out almost 800 gallons a minute of water," explained Tim Nennig, the Utility Superintendent for the Village. It's a source of pride for Nennig.

"Very little contaminant presence that we have to treat for here," he said. Nennig says when the EPA orders that testing for contaminants, the Village supply usually comes back clean. But, in 2015, the results came back with 0.545 parts per billion of 1,4 Dioxane, which the EPA identifies as a likely carcinogen. 

The EPA reports a level of 0.35 parts per billion could cause cancer in one of a million people.

"That's approximately 1 drop of this chemical in 3 Olympic size swimming pools," explained David Andrews, a scientist with the Environmental Working Group.

He said the Village of Grafton's concentration of the chemical would amount to about "two excess cases of cancer per million people."  That's about a 2.3 percent chance one person in the current population of Grafton could get cancer from the chemical. Though, per current EPA Drinking Water Standards, Grafton's water supply is safe.

"Any contaminant that the Village of Grafton finds in our drinking water, we take very seriously," Nennig tells the I-Team.

In the annual report to water users in 2016, the Village wrote "illegal dumping and spills" caused the chemical to get into the water supply.

"We always keep things in perspective, too. There are a lot of contaminants, unfortunately," Nennig said.

Though it's a small chance, Andrews says 1,4 Dioxane is just an example of chemicals in drinking water around the country unregulated by the EPA, even though they're testing for them. He wants to see more legal limits, instead of just giving guidance, on contaminants.

"This is just another example of where the federal agency has come up short in ensuring safe drinking water for all Americans," he said.

An EPA spokesperson sent the following statement to the TODAY'S TMJ4 I-Team:

 "EPA has promulgated a number of drinking water regulations since the 1996 amendments to the Safe Drinking Water Act in consultation with states, EPA’s National Drinking Water Advisory Council, the Science Advisory Board and/or other interested stakeholders.  These regulations have been designed to protect public health from issues ranging from arsenic, pathogens, and disinfection byproducts in drinking water, to public notification regarding contaminants in drinking water supplies.  For more, visit:

The Safe Drinking Water Act (SDWA) requires EPA to issue requirements for monitoring up to 30 unregulated contaminants every 5 years through the unregulated contaminant monitoring rule.  See epa.govfor more information.  EPA’s selection of contaminants for UCMR monitoring is largely based on a review of the Contaminant Candidate List (CCL).  The CCL is a list of contaminants that are known or anticipated to occur in public water systems and that may require regulation. In accordance with the Safe Drinking Water Act, EPA identifies a Contaminant Candidate List every five years.  See for more information.
EPA last issued a Drinking Water Contaminant Candidate List in 2016.  The CCL 4 is a list of 97 chemicals or chemical groups and 12 microbial contaminants that are known or anticipated to occur in public water systems and that may require regulation.  For more information, see link:
 SDWA requires EPA to consider three criteria when making a determination to regulate emerging drinking water contaminants:

  • The contaminant may have an adverse effect on the health of persons
  • The contaminant is known to occur or there is a high chance that the contaminant will occur in public water systems often enough and at levels of public health concern
  • In the sole judgment of the Administrator, regulation of the contaminant presents a meaningful opportunity for health risk reductions for persons served by public water systems"

In the meantime, Nennig said the Village keeps testing for 1,4 Dioxane, waiting for the EPA of the State's Department of Natural Resources to give guidance on 1,4 Dioxane.

"Look at removal equipment, whatever technologies are available and we'll deal with that at that time," he said.

Click here to learn about what's in your local drinking water supply.