Methylenediphenyl diisocyanate (MDI) substances
Learn about methylenediphenyl diisocyanate (MDI) substances.
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About MDI substances
MDI substances don’t occur naturally in the environment. They’re industrial substances used to make polyurethanes and polyurethane products available to both industry and consumers.
Polyurethane and polyurethane products can be used to make items such as:
- packaging wraps
- paints and coatings
- insulating products
- foam slabs used in furniture
- adhesives, including those used to make engineered wood products like wood panels
Some sealants available to consumers are known as spray polyurethane foam application products and have 2 separate chambers of chemicals in a kit. The chemicals in each chamber mix together to create the spray polyurethane foam, which is used to seal small cracks.
Safety of MDI substances
We assessed the potential health and environmental risks of 5 MDI substances through a chemical risk assessment. The assessment shows that use of MDI-based (for example, polyurethane) foam products with 2 chambers may pose a risk to your health. They may cause breathing problems and skin sensitivities.
What we’re doing
Canada is implementing a code of practice in partnership with industry and retailers to reduce exposures to MDIs.
The code sets out recommendations for actions that industry and retailers should take to inform Canadians about the safe use of these spray polyurethane foam application products.
What you can do
You can take action to minimize your exposure to MDI substances by:
- following product instructions and safety warnings
- having a work area with proper ventilation by:
- working outside if possible
- opening nearby windows
- wearing clothing that covers skin to avoid getting the product on your skin
- using proper safety equipment, such as a respirator designed to protect from MDI exposure, to avoid inhaling the substance
You may also choose to hire a professional contractor. Follow the contractor’s instructions on:
- when to leave the area when it is not safe
- when to re-enter the area when it is safe
- how to keep the area well-ventilated and for how long
If you work with industrial substances, you may be exposed to MDIs. If this is a risk, you should consult with your employer and occupational health and safety (OHS) representatives about:
- safe handling and storage practices
- applicable laws and requirements under OHS legislation and the Workplace Hazardous Materials Information System (WHMIS)
For more information
- Household chemical safety
- Measuring your exposure to chemicals
- Canada’s system for addressing chemicals
- Overview of the Chemicals Management Plan
For industry and professionals
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