U.S. EPA Contaminated Site Cleanup Information (CLU-IN)

U.S. Environmental Protection Agency
U.S. EPA Technology Innovation and Field Services Division

For more information on 1,4-Dioxane, please contact:

Deb Cox
Technology Assessment Branch

PH: 202-566-0946 | Email:


Policy and Guidance

EPA regulates 1,4-Dioxane under the Clean Air Act (CAA), Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), Resource Conservation and Recovery Act (RCRA), and Superfund Amendments and Reauthorization Act (SARA). EPA has set control technology standards for air emissions of 1,4-Dioxane, and a reportable quantity of 100 pounds has been established under CERCLA. 1,4-Dioxane is exempted from tolerances for pesticide chemicals in or on raw agricultural commodities, and it has been classified as a toxic inert ingredient of pesticide products. RCRA subjects 1,4-Dioxane wastes to reporting and record-keeping requirements.

In its 2012 Edition of the Drinking Water Standards and Health Advisories, EPA listed a health advisory of 35 µg/L for 1,4-Dioxane at a 10-4 cancer risk level. EPA also has posted generic Regional Screening Levels (RSLs) as criteria for preliminary remediation goals for 1,4-Dioxane and other contaminants. The RSL tables contain calculated screening levels for tap water, residential soil, industrial soil, residential air, industrial air, and soil-to-groundwater risk-based soil screening levels for Superfund sites. Suthersan et al. (2016) observed that 33 states had established groundwater cleanup standards for 1,4-Dioxane, and a large number of state health departments have adopted drinking water standards and advisory levels for the compound. Where cleanup standards have been established, target concentrations vary by state and by site (with some adopting values lower than 35 µg/L).

Adapted from:

Mohr, T.K.G. 2001.Solvent Stabilizers: White Paper. Santa Clara Valley Water District, San Jose, California.

RoC (Report on Carcinogens, 14th ed.). 2016.Adobe PDF Logo 1,4-Dioxane, CAS No. 123-91-1. Department of Health and Human Services.

Suthersan, S. et al. 2016. Making strides in the management of "emerging contaminants". Groundwater Monitoring & Remediation 36(1):15-25.

USEPA. 2012. Adobe PDF Logo 2012 Edition of the Drinking Water Standards and Health Advisories. EPA Office of Water, EPA 822-S-12-001.

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The Food and Drug Administration (FDA) regulates 1,4-Dioxane under the Federal Food, Drug, and Cosmetics Act as an indirect food additive when it is used as an adhesive component in packaging materials. The agency periodically monitors the presence of 1,4-Dioxane in cosmetics. FDA also makes nonbinding recommendations for Class 2 solvents in pharmaceutical products Adobe PDF Logo.

The National Institute for Occupational Safety and Health (NIOSH) has recommended an exposure limit of 1 ppm; (3.6 mg/m3) ceiling (30 minutes) for 1,4-Dioxane. The Occupational Safety and Health Administration (OSHA) set a permissible exposure limit—100 ppm, (360 mg/m3) 8-hour time-weighted average; Skin—for 1,4-Dioxane in the workplace. OSHA also regulates 1,4-Dioxane under the Hazard Communication Standard and as a chemical hazard in laboratories.

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1,4-Dioxane: Health-Based Recommended Occupational Exposure Limit
Dutch Expert Committee on Occupational Safety, Health Council of the Netherlands. 78 pp, 2011

Adobe PDF Logo 1,4-Dioxane in Drinking-Water: Background Document for Development of WHO Guidelines for Drinking-Water Quality
World Health Organization, Geneva. WHO/SDE/WSH/05.08/120, 20 pp, 2005

Canadian Water Quality Guidelines for the Protection of Aquatic Life: 1,4-Dioxane
Canadian Council of Ministers of the Environment, 5 pp, 2008

Recommendation from the Scientific Committee on Occupational Exposure Limits for 1,4-Dioxane
European Commission, SCOEL/SUM/112, 17 pp, 2004

Adobe PDF Logo Scientific Opinion on the Report of the ICCR Working Group: Considerations on Acceptable Trace Level of 1,4-Dioxane in Cosmetic Products
Scientific Committee on Consumer Safety (SCCS). SCCS/1570/15, 18 pp, 2015

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Because there are no federal regulations limiting 1,4-Dioxane in tap water or groundwater, some states have set their own criteria. Through EPA's links to the Health and Environmental Agencies of U.S. States and Territories, readers can check for the most recent information on 1,4-Dioxane in each state.

Technical Resources for Addressing Environmental Releases of 1,4-Dioxane
Interstate Technology and Regulatory Council (ITRC) Web-based document 14d-1, 2021

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