1,4-Dioxane Widespread in Long Island Drinking Water

1,4-Dioxane is an emerging contaminant of concern found in Long Island's groundwater and drinking water. It is a Synthetic Organic Compound (SOC), which is never found in nature. According to CCE's recent evaluation of public water suppliers across Long Island, Nassau and Suffolk water suppliers have reported the highest levels of 1,4-dioxane contamination in the nation. 1,4-Dioxane is listed as "likely to be carcinogenic to humans," with a Lifetime Cancer Risk Guideline for drinking water of 0.35µg/L (micrograms per Liter) by the U.S. EPA. The chemical has been linked to tumors of the liver, kidneys, and nasal cavity. Our interactive map (below) shows the highest detections of 1,4-dioxane in each water district/distribution area across Long Island.

Where Does 1,4-Dioxane Come From?

Legacy Contamination

Originally,1,4-dioxane was used as an industrial solvent stabilizer and could be found widely in paints, primers, varnishes, degreasers, and inks. Although it has been phased out of use in some of these applications, many still contain it. Groundwater plumes that contain the chemical Trichloroethane (TCA) are very likely to also contain 1,4-dioxane. According to Newsday's database of Long Island Superfund sites, there are at least 50 sites that are known to contain TCA , meaning there is a high probability they also contain 1,4-dioxane. 1,4-Dioxane does not easily degrade or break down in the environment and is highly mobile in soil and groundwater.

The Hidden Carcinogen in Everyday Products

1,4-Dioxane is lurking in everyday products. It occurs as byproduct of a manufacturing process called ethoxylation and is found in many common household products. 1,4-Dioxane was found in 65 out of 80 products (including shampoos, body washes, baby products, laundry detergents, hand and dish soaps) that CCE had independently tested earlier this year. Products tested had 1,4-dioxane levels as high as 17,000 ppb. The elevated levels found in many laundry detergents make laundromats a potential point-source of contamination for 1,4-dioxane. Some laundry detergents have been found to have the highest levels of 1,4-dioxane of any consumer products, with levels over 50 parts per million, a concentration equivalent to over 100,000 times the EPA's Cancer Risk Guideline for drinking water.

Since 1,4-dioxane is a manufacturing byproduct, it is not listed on the labels of household products, making it nearly impossible for consumers to make safe, informed choices. Consumers can look for the 'ethoxylated' ingredients, which may indicate the presence of 1,4-dioxane. The names of those ingredients often include "-eth" or "-oxynol" in part of their names, such as "phenoxyethanol." Two of the most common ingredients that are problematic for 1,4-dioxane contamination are "sodium laureth sulfate" and "potassium laureth phosphate". While manufacturers can remove 1,4-dioxane from products simply and cheaply, and the FDA recommends that manufacturers do so, many companies do not take that extra step. The FDA needs to require the removal of this chemical; it should not be a voluntary option.

Here is a more extensive list of commonly used ethoxylated ingredients:

  • Anything with "PEG"

  • Polyethylene

  • Polyethylene glycol

  • Polyoxyethylene

  • Polysorbate-20

  • Polysorbate-60

  • Polysorbate-80

  • Sodium laureth sulfate

  • Potassium laureth phosphate

  • Myreth

  • Oleth

  • Ceteareth

  • Steareth

  • Phenoxyethanol

Once down the drain, these products carry 1,4-dioxane directly into our groundwater through over 500,000 septic tanks and cesspools across Long Island. That groundwater eventually either flows outward into our surface waters or downward into our aquifers, which is the sole-source of Long Island's drinking water.