CAS Registry Number 62-56-6

The Final Screening Assessment for Thiourea was published January 31, 2009 as part of Batch 2 of the Challenge initiative of the Chemicals Management Plan (CMP). The assessment is summarized on this page.

What is it

  • Thiourea is an industrial chemical and also occurs naturally in some plants and fungi.

How is it used

  • As an industrial chemical, thiourea is used in metal finishing solutions, in the manufacture of printed circuit boards, in copper refining, and as a rust inhibitor.
  • Thiourea may also be found in black and white photographic chemicals, and silver polish/metal cleaners.
  • Based on the most recent data, thiourea is not manufactured in Canada, but it is imported into Canada.

Why did the Government of Canada assess it

  • Thiourea was identified as a potential concern to human health based on its classification by an international organization as a substance which was found to cause cancer in some studies with animals and which may impair fertility or cause developmental effects in animals.
  • Thiourea was also believed to have a high potential for exposure to Canadians.
  • Thiourea was assessed by Government of Canada scientists to help decide if further actions may be necessary so that the health of Canadians and the environment are protected.

How are Canadians exposed to it

  • Exposure to the general population is expected to be low.

What is the Government of Canada doing

  • The Government of Canada has conducted an evaluation of thiourea based on science, called a screening assessment.
  • The Government of Canada has determined that thiourea is considered to be harmful to human health.
  • Although Canadians' exposure is very low, the Government of Canada is taking action so that exposure remains low.
  • Risk management options include the development of a future notification tool so that new uses in Canada do not increase exposure for Canadians.
  • Thiourea is included as a prohibited or restricted ingredient on Health Canada's Cosmetic Ingredient Hotlist. The Hotlist is used to communicate that certain substances may not be compliant with requirements of the Food and Drug Act or the Cosmetic Regulations. Under Canadian legislation, cosmetics that contain substances that are harmful to the user cannot be sold.
  • The proposed risk management approach document was published on January 31, 2009. The proposed risk management approach will be subject to a 60-day public comment period ending April 1, 2009.
  • Up-to-date information of the risk management action milestones for thiourea is available.

What should Canadians do

  • Because exposure to thiourea is very low, Canadians do not need to take any specific actions to reduce their exposure.
  • Canadians are reminded to follow safety warnings and directions for use carefully when using products.

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