1,4-Dioxane

The Remediation Standard Regulations do not contain numeric cleanup standards for 1,4-dioxane, but do require remediation using the procedures for Additional Polluting Substances (APS).  Regulated parties and their environmental professionals should consider whether 1,4-dioxane is a constituent of concern when evaluating Phase I information for a site and test for it where warranted.  Doing so will help avoid uncertainty, audits, and further work in the future.  APS criteria for 1,4-dioxane are available on the APS Fast Track form.

Where is it 1,4-dioxane found (list is not exhaustive)?

• Associated with chlorinated solvent contamination
• Stabilizer for TCA, possibly other chlorinated solvents
• Cellulose acetate membrane filters
• Pharmaceutical industry
• Laboratories
• Car wash concentrated soaps
• Scintillation counting cocktails/ Bray’s Solution
• Histology tissue preservative
• Brominated flame retardants 
• Textiles
• Pulp, paper, and fiber manufacture, especially coated paper
• Magnetic tape production
• Inks and printing
• Painting, coating and stripping
• Polymers, plastics, and rubber
• Loosening agent for hardware
• Cutting oils, greases
• Dyes, varnishes, and waxes
• Byproduct of PET plastic, ethoxylated surfactant, resin, and antifreeze production
• Aircraft deicing fluid
• Personal care and household products as an unintentional byproduct (cleaners, detergents, shampoos, bath gels, lotions, cosmetics, liquid dishwashing soap, baby lotion)
• Landfills

Fate & Transport Characteristics of 1,4-Dioxane

• Completely soluble
• Leaches readily from soil to groundwater and migrates faster than chlorinated solvent plumes.
• Pure product is volatile, but it does not volatilize once dissolved in water.
• Because 1,1,1-trichloroethane has a short half-life, presence of its degradation products including 1,1-dichloroethene and 1,1-dichloroethane may also indicate possible presence of 1,4-dioxane.

Analytic Methods for 1,4-Dioxane

• EPA Method 522
• Environmental matrices (aqueous and solid) - EPA Method 8260 or 8270 (full scan or SIM).  Please see ITRC’s Technical Regulatory Guidance Document for 1,4-Dioxane, Section 4.2 - 1,4-Dioxane Analysis, for specific laboratory analytical method recommendations based on matrix and reporting limits needed.

Please Note:   New information about 1,4-dioxane should be expected, as research is ongoing.  You are advised to complete your own research to determine whether 1,4-dioxane is a contaminant of concern at a particular site.

Additional Resources:

Connecticut

• DPH 1,4-Dioxane in Well Water 
• CT DPH Drinking Water Action Level List for Private Wells 

Federal

• EPA CLU-IN 1,4-Dioxane Overview - numerous state and federal links regarding all aspects of 1,4-dioxane
• EPA Technical Fact Sheet on 1,4-Dioxane - general information
• EPA Final Risk Evaluation for 1,4-Dioxane – Final TSCA risk determination
• EPA Treatment Technologies for 1,4-Dioxane: Fundamentals and Field Technologies - 2006 booklet
• SERDP/ESTCP Webinar: 1,4-Dioxane Impacts and Innovative Cleanup Technologies at DoD Contaminated Sites (April 6, 2017) - top right corner of page, search for 1,4-dioxane
• SERDP-ESTCP Tools and Training - Dept. of Defense Strategic Environmental Research and Development Program-Environmental Security Technology Certification Program videos, webinars, and guidance documents

Organizations

• ITRC 1,4 Dioxane - includes fact sheets and a guidance document prepared by the Interstate Technology Regulatory Council’s 1,4-Dioxane Team

Other States

• MA DEP Emerging Contaminants - MA initiatives on emerging contaminants
• MA Fact Sheet Guidance on Sampling and Analysis for 1,4-Dioxane at Disposal Sites Regulated under the Massachusetts Contingency Plan - DEEP concurs with the information provided in the Sampling/Analysis portion of the Fact Sheet. However, the information in this factsheet should be thoughtfully considered by the LEP with respect to Connecticut’s statutes, regulations, and standard of care
• NJ DEP - Responding to Emerging Contaminants: 1,4-Dioxane
• NYS DEC:
  • Emerging Contaminants In NY's Waters
  • 1,4-Dioxane Limits for Household Cleansing, Personal Care, and Cosmetic Products - New York State has a regulation that requires household products to contain no more than 1 part per million (ppm) and cosmetics contain no more than 10 ppm of 1,4-dioxane.

Contaminants of Emerging Concern

Content last updated May 5, 2025