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Boric acid and your health

Learn about boric acid, its potential health risks and how to reduce your exposure.

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About boric acid

Boric acid is a common form of boron, a naturally occurring element found in different minerals. It's an essential micronutrient in most plants and some animals. Boric acid can be released into the environment from natural sources, including:

  • soil dusts
  • volcanoes
  • forest fires
  • fruits and vegetables
  • rock and soil weathering
  • sea salt and plant aerosols

It can also be manufactured, where it may be released from industrial processes, as well as from importing products that contain boric acid.

Boric acid can be found in many everyday items, including:

  • cosmetics
  • flame retardants
  • cleaning products
  • pest control products
  • non-prescription drugs
  • natural health products
  • arts and crafts materials and toys
  • do-it-yourself (DIY) products, such as:
    • paints and coatings
    • adhesives and sealants
    • automotive and home maintenance products
  • swimming pool and spa maintenance products

Borax is a naturally occurring mineral that may produce boric acid. It can be purchased at concentrations up to 100% and is typically used as a household cleaner and laundry product. Many DIY recipes available online use borax, or contact lens solutions containing boric acid, to make homemade:

  • slimes
  • crystal formations
  • modelling clays, play doughs and putties

There are many other chemicals used in products available to consumers that may produce boric acid. Some examples include:

  • zinc borate
  • MEA borate
  • MIPA borate
  • sodium borate
  • potassium borate
  • sodium perborate
  • ammonium pentaborate
  • sodium tetraborate decahydrate

Boron nitride, a common ingredient in cosmetics, does not produce boric acid.

Labels on many consumer products, including certain cleaning products, are not required to list ingredients. Therefore, it can be difficult to determine if the products you are using contain boric acid or chemicals that may produce it.

People in Canada are exposed to boric acid from:

  • the environment, including through food and drinking water
  • products available to consumers

Safety of boric acid

Under Canada's Chemicals Management Plan, we review and manage the potential risks that chemicals can pose to people in Canada and the environment. The first stage of the review process is a draft chemical risk assessment.

An initial draft chemical risk assessment of boric acid was completed in 2016. It proposed that boric acid is harmful to the environment and human health. Since then, new information about uses and exposures to boric acid has become available. As a result, we've updated the draft assessment.

We're proposing that boric acid may have harmful effects on human development and reproduction when it's used in certain products that may be inhaled, ingested or come into contact with the skin. These products include certain:

  • homemade crafts and toys containing boric acid, such as:
    • slimes
    • crystal formations
    • modelling clays, play doughs and putties
  • arts and crafts materials and toys, including many that are marketed to children or teachers, such as:
    • glues
    • paints
    • slimes
    • modelling clays, play doughs and putties
  • cleaning products, such as:
    • abrasive powders
    • general purpose powder cleaners
    • carpet or floor cleaning or spot-removing powders
    • laundry products
  • flame retardants used in mattresses or futons
  • rust paint that's applied with an airless sprayer
  • self-care products, such as:
    • eye drops
    • massage oils
    • mouth washes
    • permanent hair dyes
    • body and face lotions
    • anti-hemorrhoid cream
    • oral health supplements
    • hair removal aftercare products
  • swimming pool and spa maintenance products

Using these products may expose you to boric acid well above any exposure from food, drinking water or the environment.

Children and people who are assigned male at birth are at highest risk of health impacts from boric acid in products available to consumers.

Natural sources of boric acid in fruits and vegetables are not considered a concern to people's health. People in Canada should continue to eat a variety of foods each day to maintain good health.

What we're doing

Our assessment is not yet final. We're continuing to evaluate the potential risks posed by boric acid before we publish our final conclusion. This includes:

  • tracking new information on exposures or hazards
  • asking the public to comment on our draft assessment
  • reviewing and using new information and public comments to help inform our final assessment

Canada already has measures in place that limit the amount of boric acid allowed in some products available to consumers, including:

  • cosmetics
  • children's toys
  • non-prescription drugs
  • natural health products

Canada has also cancelled and phased out certain pest control products that contain boric acid and imposed stronger label requirements to protect human health.

If the proposed findings for boric acid are confirmed in the final assessment, we will consider further actions, such as:

  • adding it to Schedule 1 of the Canadian Environmental Protection Act, 1999
    • this would allow Canada to implement preventive or control actions for the lifecycle of the substance, including:
      • research and development
      • manufacture
      • use
      • storage
      • transport
      • disposal or recycling
  • changing its entry on the Cosmetic Ingredient Hotlist
    • this would provide information to manufacturers on the further restriction or prohibition of the use of boric acid in cosmetics
  • reviewing the maximum daily dose allowed and associated conditions of use for boron under the joint health product monographs for multi-vitamin and mineral supplements and multiple ingredients
  • changing its entries on the Natural Health Products Ingredients Database
    • this would provide information to manufacturers on the further restriction or prohibition of the use of boric acid in natural health products and non-prescription drugs

We will also consider taking action to help:

  • reduce exposures to boric acid from homemade clays, slimes and crystals intended for children's use
    • this may include public education to discourage the use of boric acid in arts and crafts
  • reduce or eliminate exposures from mattresses or futons containing boric acid used as a flame retardant
  • reduce exposures to certain products available to consumers containing boric acid, including:
    • cleaning products, such as:
      • laundry powders
      • abrasive powders
      • floor cleaning powders
      • carpet spot remover powders
      • general purpose powder cleaners
    • swimming pool or spa water treatment chemicals
    • DIY products, specifically rust paints that are applied with an airless sprayer

You may provide any comments on our risk management scope during the 60-day public comment period.

What you can do

You can take steps to reduce your exposure to harmful chemicals.

When making children's arts and crafts at home like slimes, use recipes that do not contain boric acid, borax or contact lens solution.

Read product labels and follow all safety warnings and directions:

  • labels on cosmetics, natural health products and non-prescription drugs must list all ingredients and instructions for use
    • look out for ingredients such as:
      • borax
      • boric acid
      • borate or chemical names that this term
    • boron nitride, a common ingredient in cosmetics, does not produce boric acid and is not considered harmful to human health

Follow the manufacturer's directions to use and dispose of the product safely.

Store cleaning products and pesticides out of sight and reach of children.

Do not make homemade pesticides using boric acid.

Make sure you use only registered pesticides that have a Pest Control Products Act (PCP) registration number on the label:

  • you can access pesticide labels on your mobile device using the pesticide label search mobile app
  • only use pesticide products in and around the home in areas that children and pets can't access, such as:
    • behind appliances
    • in cracks and crevices
    • in bait stations that are enclosed

If you're not sure your product contains boric acid or substances that may produce boric acid, contact the manufacturer.

If you're exposed to boric acid at work, talk to your employer and occupational health and safety (OHS) official about:

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