1,4-Dioxane (commonly referred to as simply ‘dioxane’) is used as a solvent in the manufacture of other chemicals and as a laboratory reagent. It is a trace contaminant of some chemicals used in cosmetics, detergents, and shampoos. (4)
Belongs to the class of organic compounds known as 1,4-dioxanes. These are organic compounds containing 1,4-dioxane, an aliphatic six-member ring with two oxygen atoms in ring positions 1 and 4.
Though the mechanism of toxicity of 1,4-dioxane has not yet been elucidated, it is known that its carcinogenic effects are caused by a non-genotoxic mechanism that is most likely cytotoxic in nature. (4, 6)
Metabolism
Exposure to 1,4-dioxane may occur by inhalation, ingestion, and to a lesser extent by dermal contact. 1,4-Dioxane is quickly absorbed and metabolized to beta-hydroxyethoxyacetic acid (HEAA) by mixed-function oxidase enzymes. HEAA can then be converted to 1,4-dioxane-2-one under acidic conditions. Both of these products are rapidly and extensively eliminated in the urine (>95%). Unchanged 1,4-dioxane can also be excreted in the urine and in exhaled air, but mainly after high-dose exposure. (4)
1,4-Dioxane is primarily used in solvent applications for the manufacturing sector; however, it is also found in fumigants and automotive coolant. 1,4-Dioxane is a byproduct of the ethoxylation process in cosmetics manufacturing, thus many products on the market today contain 1,4-dioxane in very small amounts. However, some cosmetics, detergents, and shampoos may contain 1,4-dioxane at levels higher than recommended by the FDA for other products. 1,4-Dioxane can also be found in tap water, so human exposure to 1,4-dioxane may also occur during activities such as showering, bathing, and laundering. (4, 5)
Minimum Risk Level
Not Available
Health Effects
1,4-Dioxane for short period of time cause eye and nose irritation at low levels, and severe kidney and liver effects and possibly death at very high levels. For long-term exposure, studies in animals have shown that breathing vapors of 1,4-dioxane, swallowing liquid 1,4-dioxane or contaminated drinking water, or having skin contact with liquid 1,4-dioxane affects mainly the liver and kidneys. Studies in workers did not indicate whether 1,4-dioxane causes cancer, but animal studies suggest that it is a probable human carcinogen. (4)
Symptoms
1,4-Dioxane causes eye and respiratory tract irritation. (5)
