1,4-Dioxane

CAS Registry Number 123-91-1

What is it?

• 1,4-Dioxane is an industrial chemical which may also be present in some consumer products as a residual (leftover from manufacturing process).
• This substance is not related to the chemicals called Polychlorinated Dibenzodioxins and Polychlorinated Dibenzofurans - PSL1, a group of substances that have already been assessed by the Government of Canada under the First Priority Substances List and determined to be harmful to human health and for the environment.

How is it used?

• 1,4-Dioxane is primarily used as a solvent in the manufacture of pharmaceuticals, veterinary drugs and natural health products, for research and development and as an analytical reagent for laboratory use.
• It may also be found as an impurity in ethoxylated substances which are used in numerous industries (manufacturing of personal care products, detergents, pesticides, food packaging and additives, etc.).
• 1,4-Dioxane is manufactured in and imported into Canada.

Why did the Government of Canada assess it?

• Prior to the assessment, 1,4-dioxane was identified as a potential concern for human health based on its classification by international organizations as a substance which may cause cancer in laboratory animals, and based on a high potential for exposure (not including workplace exposures) to the general population of Canada.

How are Canadians exposed to it?

• The general population of Canada may be exposed to 1,4-dioxane from environmental media (ambient air, indoor air and drinking water), from various foods, from pharmaceuticals and natural health products, and during the use of consumer products such as personal care and household products containing this substance.

What are the results of the assessment?

• The Government of Canada has conducted a science-based evaluation of 1,4-dioxane, called a screening assessment.
• The Government of Canada has concluded that 1,4-dioxane is not harmful to the health of the general population at current levels of exposure.
• The Government of Canada has also concluded that 1,4-dioxane is not entering the environment in a quantity or under conditions that constitute a danger to the environment.
• Screening assessments address potential for harm to the general population (not including workplace exposures).

What is the Government of Canada doing?

• Although exposure of the general population of Canada is low, the Government proposes action so that exposure remains low (e.g., use of periodic market surveys/analysis for 1,4-dioxane impurities in cosmetics).
• The Government of Canada also proposes to investigate the utility of adding 1,4-dioxane to the Environmental Emergency Regulations of CEPA 1999 due to its high-volume use, so that emergency preparedness and response requirements are put in place.
• 1,4-Dioxane is on the Health Canada's Cosmetic Ingredient Hotlist, which is the list of ingredients that are intended to be prohibited or restricted for use in cosmetics, including many personal care products. Under Canadian legislation, cosmetics that contain substances that are harmful to the user cannot be sold.
• 1,4-Dioxane is also included in Canada's National Pollutant Release Inventory (NPRI). The NPRI is Canada's legislated, publicly-accessible inventory of pollutants released, disposed of and sent for recycling by facilities across the country. Industrial, institutional and commercial facilities which meet legislative NPRI reporting requirements must notify Environment Canada of any releases of substances of concern.
• The final screening assessment report was published on March 6, 2010.

What can Canadians do?

• The health risks associated with a chemical depend on the hazard (its potential to cause health effects) and the dose (the amount of chemical to which you are exposed).
• 1,4-Dioxane is not intentionally added to products but may be present as a by-product of the manufacturing process. The general population of Canada are only exposed to trace amounts in consumer products.
• 1,4-Dioxane is not a concern for the environment or human health at current levels of exposure. However, Canadians are reminded when using any product, to carefully follow any safety warnings and directions.
• Canadians who handle 1,4-dioxane in the workplace should consult with their occupational health and safety representative about safe handling practices, applicable laws and requirements under the Workplace Hazardous Materials Information System.