CAS Registry Number 123-31-9

What Is It?

  • Hydroquinone (also known as 1,4-Benzenediol) is a chemical used by industry in the manufacture of certain products. It also occurs naturally in some food.
  • This substance is not the same as benzene which has already been determined to be "toxic" and is regulated under the Canadian Environmental Protection Act, 1999.

How Is It Used?

  • Hydroquinone is used in the production of other chemicals. It is also used in a variety of industrial and consumer adhesives, including as an additive to heat shrink tubing, restorative paste, bonding tape and as a reducing agent in photographic developing solutions.
  • Hydroquinone is also used in certain cosmetic products such as manicure preparations and hair dyes.
  • Hydroquinone is also used in some health products such as skin lightening preparations.
  • While hydroquinone occurs naturally in some foods, there is no evidence to show that the natural presence of hydroquinone in food poses a health risk to Canadians or that Canadians should avoid foods containing hydroquinone.
  • Based on the most recent data, hydroquinone is manufactured in Canada and imported into Canada.

Why Did the Government of Canada Assess It?

  • Hydroquinone has been shown to cause cancer in some studies with laboratory animals.  Although exposures to Canadians are low, the Government of Canada's objective is to minimize exposures to this substance. 

What Is the Government of Canada Doing?

  • The Government of Canada has declared hydroquinone "toxic" as defined under the Canadian Environmental Protection Act, 1999.
  • The Government of Canada will propose additional measures to control any risks posed by hydroquinone including:
    • Proposing to regulate hydroquinone-containing health products as a prescription drug rather than allowing products containing it to be sold over the counter (e.g., skin lightening products).
    • Proposing additional restrictions on cosmetic uses to address hair dyes and nail systems consistent with restrictions already in place in the European Union. Hydoquinone is already prohibited for use in cosmetics applied to the skin or mucous membranes.
  • To keep exposures low, the Government of Canada will propose the creation of a provision so that any proposed new use of hydroquinone would be subject to notification of the federal government. With this provision the government can set conditions or prohibit the use of hydroquinone if the use would increase exposure to Canadians.

What Canadians Can Do

  • Canadians who use photographic chemicals should read and carefully follow the safety instructions provided on the label before each use.
  • Canadians who use skin lightening preparations containing 1,4-benzenediol (hydroquinone) should discuss the safe use of the product with their pharmacist at the point of purchase and closely follow instructions on the label. If Canadians are concerned about using hydroquinone, they can review the list of ingredients to determine if it is found in the product.
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