• Often referred to as “spray foam”, expanding foam is applied using a spray canister and is used  as insulation, as a sealant, an adhesive, for casting objects, and for product packaging. 1


  • Expanding foam is synthetically produced with chemicals derived from petroleum. During application, two sides of liquid chemical are combined to produce the foam effect. Side A consists of isocyanates, such as polymeric methylene diphenyl diisocyanate (pDMI). Side B contains a mixture of polyols, amine catalysts, propellant, surfactants and flame retardants. Product contents may vary depending on the type of spray foam. 2, 4


  • Spray foam is extremely dangerous to aquatic life. Foam dust, shavings, and flame retardant chemicals can enter waterways, and negatively affect the health of aquatic organisms and other animals or humans which consume them. 6

Human Health

  • Isocyanates are listed as potential human carcinogens, causing breathing issues from mild to severe asthma, as well as irritation of the skin and mucous lining of the throat and lungs. Amine catalysts can cause blurred vision and severe internal burns if ingested. Polyols can affect the central nervous system and may cause vomiting. 6

Social Equity        

  • Utilizing expanding foam as an insulator makes a building more efficient and according to the EPA could save the 15-20% on a building’s monthly energy costs. 2, 3

Safe Use and Exposure


  • While the foam is drying there is a potential for exposure. Wear protective equipment as described on the product’s label. This usually includes full-coverage clothing and dust masks. 4


Proper disposal

  • Store upright at room temperature with the manufacturer’s standards. Empty cans may be disposed of as non-hazardous waste. Do not throw out partially or unused cans, as they are highly pressurized. Donate usable amounts to the givetake.4

Safe Alternatives

  • While expanding foam is considered very “green” for its energy saving capabilities, many of the chemicals are distilled from petroleum and are toxic to both animal and human life. For a slightly safer option, use soy-oil based foams.7


  1. “What is Expanding Foam?”, Wisegeek,
  2. “Chemicals in spray polyurethane foam: How can something so toxic be considered green?”,,
  3. “Energy Efficiency”,,
  4. “FAQ”, Spray Polyurethane Foam HEALTH and SAFETY,
  5. “Isocyanates”, NIOSH,
  6. “The Environmental Impacts of Polyurethane Foam”, Synonym,
  7. “Soy Based Foam Insulation: What It Is, and Why You Should Use It”, The Greenest Dollar,