1,4 Dioxane
1,4-dioxane is a man-made chemical used by industry. It does not occur naturally in the environment. 1,4-dioxane is a colorless, flammable liquid with a mild odor that easily dissolves in water.
1,4-dioxane is use as a solvent and in chlorinated solvent stabilizer, pharmaceuticals, and adhesives. It is found in lacquers, paints, dyes, resins, waxes, grease, and a small amount is found in cosmetics, detergents, and other consumer products.
Most of the 1,4-dioxane that is found in air comes from industrial processes that use the chemical. 1,4- dioxane does not stick to soil and can enter surface water or groundwater. It can migrate rapidly in groundwater and is relatively resistant to degradation in the environment. 1,4-dioxane has been detected in groundwater in the US, including Wisconsin.
People who work in an industry that uses 1,4-dioxane have the greatest risk of exposure by breathing. People in non-work settings may also be exposed to low levels in the air when using products that have 1,4-dioxane in them. If 1,4-dioxane concentrations are high enough in household water, people may be exposed to chemical vapors while showering or bathing.
1,4-dioxane can be absorbed through the skin if consumer products such as cosmetics and detergents that contain small amounts of the chemical are used on the body.
Air
There is no federal standard for 1,4-dioxane in air. The Wisconsin Department of Natural Resources (DNR) regulates the amount of 1,4-dioxane that can be released by industries into outdoor ambient air. 1,4-dioxane-containing products should be used for short periods of time, in small amounts, and in well-ventilated areas.
Water
There is no federal drinking water standard for 1,4-dioxane.
The Wisconsin groundwater standard for 1,4-dioxane is 3 parts per billion (ppb). However, in 2019, Department of Health Services (DHS) recommends a groundwater standard of 0.35 micrograms per liter (µg/L) based on updated scientific information. DHS recommends that people take action to reduce exposure when the level in drinking water are equal to or greater than 0.35 µg/L. This action may include finding an alternative source of water or installing a treatment device certified to remove 1,4-dioxane.
Few studies are available that examine the effects of 1,4-dioxane in humans. What is available shows exposure to very high levels of 1,4-dioxane can result in drowsiness and liver and kidney damage. Eye and nose irritation have been reported by people inhaling low levels of 1,4-dioxane over short periods of time.
Studies in laboratory animals have also demonstrated that exposure to 1,4-dioxane can result in liver and kidney damage. Animals exposed to 1,4-dioxane also experienced nasal irritation and inflammation.
The US EPA considers 1,4-dioxane “likely to be carcinogenic” by all routes of exposure. In studies of laboratory animals exposed to 1,4-dioxane in drinking water for most of their lifetime, rats and mice developed liver cancer and the rats also developed nasal tumors. Studies in humans that have looked at the ability of 1,4-dioxane to cause cancer are inconclusive.