Polyurethane foam comes in many forms, including cushion material inside shoes and packaging materials inside shipping boxes. A form of this foam called spray polyurethane foam is commonly used as insulation material in buildings. This spray foam contains many chemicals that harm humans and other organisms. Spray polyurethane foam is made by combining two mixtures called Side A and Side B. Each mixture contains a cocktail of chemicals that can cause lung irritation, visual problems, burns to internal organs, vomiting and convulsions. Once solidified, the chemicals are trapped in the solid foam, but improper mixing of chemicals results in active chemicals that are still toxic. In addition, dust and shavings from the improperly mixed foam can release unreacted chemicals into the environment. These chemicals make their way into waterways and accumulate in aquatic life and organisms that feed on aquatic life.
Side A Chemicals
Side A chemicals are mainly isocyanates, including methylene diphenyl diisocyanate. Isocyanates can cause breathing problems from mild asthma to severe asthma attacks. Isocyanates irritate skin, the mucus lining the throat and the lungs. They can also cause tightness of the chest and difficulty breathing. Some have been shown to cause cancer in animals. Isocyanates are listed as potential human carcinogens.
Side B Chemicals
Side B chemicals include amine catalysts, polyols and flame retardants. Amine catalysts can cause blurred vision. If ingested, amine catalysts can cause severe burns to the mouth, throat, esophagus, stomach and intestines. Polyols are also catalysts in Side B chemicals. Both amine catalysts and polyols speed up chemical reactions to solidify the foam. Acute exposure to polyols causes vomiting and convulsions and affects the central nervous system. The flame retardants in Side B chemicals can have low toxicity after acute exposures but build up in fat, liver and brain tissue in animals.
Bioaccumulation of Flame Retardants
Side B contains flame retardants that are notorious for getting into waterways and accumulating in animals. Common flame retardants in Side B include hexabromocyclododecane and tris (1-chloro-2-propyl) phosphate. These chemicals are fat soluble and accumulate in the fat tissue and liver tissue of aquatic organisms and in humans who ingest those organisms. HBCD has been found to accumulate in the liver of Norwegian cod. TCPP has been found in low levels in blue mussels. These animals inhabit waters that are near densely populated urban areas.
Toxic to Aquatic Life
The flame retardant HBCD that is released from polyurethane foam negatively affects the survival and reproductive health of many aquatic animals. HBCD has been shown to harm the survival and reproduction of algae, daphnids and annelid worms. In fish, HBCD alters hormonal status and affects liver enzymes and it has been reported to alter thyroid hormones in salmon. HBCD can last for months in the air or for days in the soil. In water, HBCD is believed to have a half-life greater than 182 days.
- Tree Hugger: Chemicals in Spray Polyurethane Foam
- United States Department of Labor: Isocyanates
- Norwegian Institute for Water Research: Contaminants in Coastal Waters of Norway 2002
- Australian Department of Health: HBCD Factsheet
- Environment Canada: Screening Assessment Report on Hexabromocyclododecane
About the Author
David H. Nguyen holds a PhD and is a cancer biologist and science writer. His specialty is tumor biology. He also has a strong interest in the deep intersections between social injustice and cancer health disparities, which particularly affect ethnic minorities and enslaved peoples. He is author of the Kindle eBook "Tips of Surviving Graduate & Professional School."