Optimizing Recycling of Flexible Polyurethane Foam
Rebecca Stamm - April 11, 2016
Flexible polyurethane foam (FPF) is found in nearly all upholstered furniture and mattresses, in car seats, and in carpet cushion. About 600,000 tons are incorporated into products purchased in the United States each year. At the end of life, these mattresses, carpet cushions, and articles of furniture make their way into the waste stream for disposal, but some of the foam is diverted and reused in new products, mainly carpet pads. While in many cases, the recycling of wastes into new products is a welcome practice, manufacturers have long added toxic flame retardants to polyurethane foam, which then is incorporated into carpet pads. The industry’s practice of mechanically recycling this scrap has been found to elevate workers’ body burdens of flame retardants and can disperse these highly toxic substances into the global environment. Building occupants, particularly crawling children, can be exposed to flame retardants released from carpet pad.
In a new white paper produced in collaboration with StopWaste of Alameda County, the Healthy Building Network explores this waste stream, its challenges, and potential pathways for optimizing the recycling of FPF scrap.
Waste FPF Used in Carpet Cushion
Most post-consumer waste FPF is landfilled or burned, but some old carpet cushion is diverted from disposal as post-consumer scrap. Additionally, some regions are seeing an increase in post-consumer FPF available from mattress recycling due to new mattress recovery programs. Most post-consumer FPF scrap that is recovered for recycling is mixed with post-industrial scrap (out of spec foam from manufacturing, trim scrap from furniture production, etc.) and used to produce bonded carpet cushion, also known as rebond. Rebond is created by shredding foam into small pieces that are molded together with a polyurethane-based binder.
From 1975 until 2014, the open flame requirement of California TB 117, which had become the de facto national standard, led to the incorporation of large quantities of halogenated flame retardants into upholstered furniture foam. Post-industrial scrap foam from this industry was recycled into bonded carpet cushion, taking with it the additive flame retardants. With the recent changes to TB 117, flame retardant free post-industrial scrap is becoming available (although the phase-out is by no means complete). However, as carpet cushions reach their end of life, many are then reincorporated back into new bonded carpet cushion as post-consumer scrap, continuing to contaminate new products with legacy flame retardants.
HBN GRAPHIC BASED ON CARPET CUSHION COUNCIL AND CALRECYCLE DATA
Fate and Impacts of Flame Retardants in Carpet Cushion
Discussions about flame retardant content in bonded carpet cushion have primarily centered around a chemical called pentabromodiphenylether, or PentaBDE. This brominated flame retardant was introduced to carpet cushion through incorporation of post-industrial furniture foam until health concerns led to its phase-out in 2005. Since then, it has continued to be incorporated, in decreasing quantities, through post-consumer content.
PentaBDE is not the only concern, however. Manufacturers have replaced it with a suite of other flame retardants in order to continue to meet flammability standards for upholstered furniture. As post-industrial furniture foam was incorporated into carpet cushion, so too were these replacement flame retardants. Firemaster 550, TDCPP, TCEP, TCPP, and V6 have been identified in studies of furniture foam, and these replacement flame retardants have been found to be similarly toxic to the substance they replaced. All are halogenated flame retardants, a class which has been identified as persistent and bioaccumulative.
Many organizations, including the U.S. Environmental Protection Agency and the United Nations, have expressed concerns about consumers’ continued exposure to these hazardous flame retardants through reincorporation of recycled materials into new products. “Millions of pounds of foam that is flame retarded with pentaBDE or an alternative have been, and will be, sold and used in homes throughout the United States as carpet cushions. Direct exposure to millions of consumers from these sources is possible,” warned the EPA in 2005. The report explains, “as carpet padding ages, foam dust will be generated and become airborne with traffic on carpet. This presents a particular exposure potential for children, who spend time on the floor.” Additionally, the flame retardants volatilize and are deposited onto household dust, which creates further potential exposure. A 2016 study indicates that inhalation is also a significant exposure route for several of the replacement flame retardants.
There are also concerns about worker exposure to hazardous flame retardants (a 2008 study found that FPF recycling workers and people who install rebond carpet cushion had levels of PBDEs an order of magnitude higher than the general public) and dispersion of these chemicals into the environment during the recycling process.
No studies on the exposure of recycling workers or releases to the environment were found for the replacement flame retardants. There is minimal information available on the amount or degree of carpet cushion contamination with replacement flame retardants, but based on their extensive use in furniture foam, it is expected to be very significant. In 2014, the state of Washington tested for and identified replacement flame retardants in new carpet cushion. Of the five products tested, all contained at least four different flame retardants with total flame retardant content ranging from 0.4-8.6% by weight (4,000-86,000 ppm).,
More research is needed in a variety of areas, including understanding flame retardant use in mattress foam, developing field testing techniques to screen for chlorinated flame retardants, and developing chemical recycling means that remove additives of concern like flame retardants. Meanwhile, more can be done to label and track products and scrap foam as to their flame retardant content.
The recycling of materials can offer many advantages over other waste management options, but the benefits of recycling must be weighed against negative impacts on humans and the environment. There is no easy solution to the problem of flame retardant contaminated foam, but there is an opportunity to develop pathways for dealing with current contaminated foams and assure clean future feedstocks. Any methods for recycling or disposal of contaminated foams should ensure no discharge of hazardous materials to humans or the environment.
Our white paper concludes that, “Because of contamination of the main component of the post-consumer FPF feedstock (bonded carpet cushion) with toxic flame retardants, use of these materials in building applications is not recommended unless it can be verified that flame retardant content in the end product is less than 0.01% (100 ppm) by weight, and that workers are protected from exposure to flame retardants.”
Please see the full white paper for a detailed analysis of post-consumer flexible polyurethane foam as a feedstock for building products and detailed recommendations for stakeholders.
 Yang, Wenqing, Qingyin Dong, Shili Liu, et al. 2012. Recycling and disposal methods for polyurethane foam wastes. Procedia Environmental Sciences 16: 167-175. & Polyurethane Recycling, American Chemistry Council, http://polyurethane.americanchemistry.com/Sustainability/Recycling ;
Haines, G. William. “Re: Comments of the Carpet Cushion Council on EPA’s Proposal on Certain Polybrominated Diphenyl Ethers, Significant New Use Rule and Test Rule.” Memorandum, Carpet Cushion Council, July 31, 2012. https://www.pharosproject.net/uploads/files/sources/1828/1360950560.pdf.
 California’s flammability requirement for upholstered furniture
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United Nations Industrial Development Organization. “Guidance on Best Available Techniques and Best Environmental Practices for the Recycling and Disposal of Articles Containing Polybrominated Diphenyl Ethers (pbdes) Listed Under the Stockholm Convention on Persistent Organic Pollutants,” 2012. https://www.unido.org/fileadmin/user_media/Services/Environmental_Management/Stockholm_Convention/Guidance_Docs/UNEP-POPS-GUID-NIP-2012-BATBEPPBDEs.En.pdf.
 US EPA. “Flame Retardants Used in Flexible Polyurethane Foam: An Alternatives Assessment Update,” August 2015. http://www.epa.gov/sites/production/files/2015-08/documents/ffr_final.pdf;
Clean and Healthy New York, Clean Water Action, and Conservation Minnesota. “Flame Retardants in Furniture, Foam, Floors: Leaders, Laggards, and the Drive for Change,” December 2015. http://media.wix.com/ugd/a2c2a6_d711fbd12db640c1bbc4b5471c4b2d98.pdf.
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 US EPA. “Furniture Flame Retardancy Partnership: Environmental Profiles of Chemical Flame-Retardant Alternatives for Low-Density Polyurethane Foam,” September 2015. http://www.epa.gov/sites/production/files/2015-04/documents/ffr_foam_alternatives_vol1.pdf.
 Schreder, Erika D., Nancy Uding, and Mark J. La Guardia. “Inhalation a Significant Exposure Route for Chlorinated Organophosphate Flame Retardants.” Chemosphere 150 (2016): 499–504.
 Stapleton, Heather M, Andreas Sjödin, Richard S Jones, et al. 2008. Serum levels of polybrominated diphenyl ethers (PBDEs) in foam recyclers and carpet installers working in the United States. Environmental science & technology 42, no. 9: 3453-3458.
 “Commercial Pentabromodiphenyl Ether: Risk Management Evaluation”, UNEP Persistent Organic Pollutants Review Committee, http://chm.pops.int/Portals/0/download.aspx?d=UNEP-POPS-POPRC.3-20-Add.1.English.pdf
 Van Bergen, Saskia and Stone, Alex. “Flame Retardants in General Consumer and Children’s Products,” June 2014. https://fortress.wa.gov/ecy/publications/documents/1404021.pdf.
 Bonded cushion is a heterogeneous material. The results for the area tested may not be representative of the entire product and are expected to vary greatly between products. For this testing, samples were ground to create a homogeneous test sample. PBDE’s, TDCPP, TCPP, TCEP and V6 were all identified in the carpet cushion samples. TPP (a component of Firemaster 550) was also identified in the samples but the other components of Firemaster 550 (TBB and TBPH) were not tested for.
Rebecca Stamm is a Researcher for the Healthy Building Network.