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

Federal

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

Contaminants of Emerging Concern

Content last updated May 5, 2025