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Bigger Not Always Better for Toxic Chemicals: Study finds “Green” Flame Retardant Breaks Down into Possibly Harmful Products

January 9, 2019

ESSEN, GERMANY —  January 9, 2019

It’s not easy being green. Kermit the Frog probably didn’t have chemistry in mind when he sang that line, but according to researchers from Germany, the phrase rings true for a purportedly “green” flame retardant. Many everyday products contain flame retardant chemicals which are often found to be toxic to humans and ecosystems. A new peer-reviewed study published today in Environmental Science & Technology, found that heat and ultraviolet light can break down a flame retardant marketed as eco-friendly into smaller, potentially harmful chemicals.

The flame retardant studied, called PolyFR, is a large polymer that is less likely to enter cells or accumulate in the food chain than previous flame retardants. Because of the bulky size of its molecules, PolyFR is billed as an environmentally preferable flame retardant for use in building insulation under brand names including GreenCrest, Emerald Innovation 3000, and Polymeric FR. However, little is understood about the long-term behavior of the compound. The study’s authors discovered that heat or ultraviolet light—which could be encountered during PolyFR’s use as insulation in a hot attic or after its disposal in an open landfill—could break the long chemical chain into smaller, likely more harmful products.

“Our findings are important because even a loss of 1% of PolyFR’s mass can lead to significant amounts of degradation products over several years,” said Christoph Koch, lead author of the study and a researcher at the University of Duisburg-Essen. “Given that over 26,000 tons of PolyFR are produced each year, our research suggests that the environmental impact of this flame retardant is larger than anyone suspected. The results will become even more important if this flame retardant or similar ‘chemical cousins’ are used in products with direct human exposure, for example in textiles.” Supervisor Prof. Bernd Sures adds, “We conclude that the evaluation of a polymeric flame retardants needs to include possible degradation products throughout its whole life cycle to be able to guarantee an environmentally friendly handling.”

“These results are part of a large and concerning trend,” said Dr. Joe Charbonnet of the Green Science Policy Institute, who was not involved in the study. “Manufacturers often stop using a chemical once its negative health effects come to light, only to replace it with a similar chemical which later turns out to also be toxic or have toxic degradation products. This phenomenon is called regrettable substitution.”

In order to study how the larger PolyFR could break down into smaller chemicals in the real world, researchers subjected the flame retardant to a balmy 60 °C (140 °F) temperature and shined ultraviolet light on it. They detected 75 different degradation products, including some which contained bromine. “The smaller brominated compounds might be harmful to humans, especially when exposed to a mixture of these degradation products over a long period of time,” said Koch. Due in part to concerns about the toxicity of this and similar chemicals, the California State Fire Marshal recently recommend that the state’s Building Standards Commission allow the use of flame retardant-free foam insulation underground.

“All well-studied organohalogen flame retardants [which contain bromine or chlorine bound to carbon] have been found to be harmful,” according to Dr. Arlene Blum of the University of California, Berkeley Chemistry Department and Green Science Policy Institute. “Instead of using harmful chemistries to make large molecules that can break down to toxic smaller molecules, these findings should encourage manufacturers to look for truly innovative design solutions or other safer alternatives.”


  • Christoph Koch, University of Duisburg-Essen, T: +49 (201) 183-3201; email: [email protected]
  • Bernd Sures, Prof., University of Duisburg-Essen, email:[email protected]
  • Joe Charbonnet, Ph.D., UC Berkeley & Green Science Policy, T: (812) 855-5273; email: [email protected]
  • Arlene Blum Ph.D., UC Berkeley & Green Science Policy, T: (510) 919-6363; email: [email protected]