CLU-IN.ORG | Contaminant Focus: 1,4-DIOXANE, Overview

1,4-Dioxane (C₄H₈O₂, CAS No. 123-91-1) also can be identified as dioxane, dioxan, p-dioxane, diethylene dioxide, diethylene oxide, diethylene ether, or glycol ethylene ether.

A colorless, flammable liquid with a faint, pleasant odor, the synthetic industrial chemical is used as a solvent for extracting animal and vegetable oils and in the formulation of inks, coatings, and adhesives. In the laboratory, 1,4-dioxane is useful as a cryoscopic solvent for molecular mass determinations and as a stable reaction medium for diverse reactions. 1,4-Dioxane is used primarily as a solvent in paints, varnishes, lacquers, cosmetics, deodorants, cleaning and detergent preparations, and in scintillating fluids. Literature searches also indicated the potential for use as a solvent in the processing of crude petroleum, petroleum refining, petrochemicals, pulp and paper, explosives, commercial printing, electroplating/polishing, pesticide and agricultural manufacture, dyes, fiber manufacture, pharmaceuticals, adhesives, semiconductors, electronic components, photographic equipment, magnetic recording media, polymers, plastics, rubber manufacture, and organic and inorganic chemical manufacture. 1,4-Dioxane often has been used with chlorinated solvents, particularly 1,1,1-trichloroethane (TCA), as a stabilizer and corrosion inhibitor.

When 1,4-dioxane is used as a solvent stabilizer, the solvent itself is regulated as hazardous waste. When applied as an additive, 1,4-dioxane is not used for its solvent properties and does not meet the regulatory definition of solvent. 1,4-Dioxane generally is listed with a group of pollutants in state and federal guidance for air pollution control and release reporting and in water pollutant control and National Pollutant Discharge Elimination System (NPDES) permitting.

1,4-Dioxane is highly flammable and potentially explosive if not stored properly. The chemical is a cyclic ether that is highly miscible in water; in fact, it mixes with water so readily that it can be found in ground-water plumes far in advance of any solvents with which it might have entered the subsurface originally. It also migrates rapidly in soil. 1,4-Dioxane contamination often can be found in association with releases of chlorinated solvents.

EPA has listed the compound as a probable human carcinogen based on the results of animal studies, but little information is available on the long-term effects of 1,4-dioxane on human health.

The compound does not respond to air stripping or granular activated carbon treatment, nor does it biodegrade in the subsurface other than very slowly. Researchers are developing new treatment technologies for 1,4-dioxane, but advanced oxidation processes involving hydrogen peroxide and ultraviolet light or ozone have been applied successfully, and phytoremediation shows promise for its removal at depths accessible to plant roots.

Adapted from:

Memorandum: 1,4-Dioxane Action Level
G. Alexeeff, California Office of Environmental Health Hazard Assessment, 1998.

Solvents Study
U.S. EPA, Office of Solid Waste, 1996.

1,4-Dioxane: Priority Existing Chemical No. 7
National Industrial Chemicals Notification and Assessment Scheme.
AusInfo, Commonwealth of Australia, ISBN: 0-642-47104-5, 125 pp, 1998.

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Last updated on Wednesday, July 21, 2004