Healthier Insulation


Learn about the history, fire safety, health and environmental issues of flame retardants in building insulation. Download references for this video.


Problem: For improved energy efficiency, the use of foam plastic insulation materials such as polystyrene, polyisocyanurate, and polyurethane is increasing in buildings, especially “green” buildings. Outdated flammability standards in building codes lead to the addition of flame retardant chemicals that are either known to be toxic or lack adequate health and environmental information. These chemicals do not increase fire safety when used below grade or behind thermal barriers.We have been working with architects, builders, policymakers and fire safety experts to create healthier buildings by finding ways to reduce the use of flame retardants in building materials when they do not improve fire safety.


Flame retardant chemicals in building insulation

The brominated flame retardant HBCD is added to all expanded and extruded (EPS and XPS) and other polystyrene insulation. It bioaccumulates in fat, becoming more and more concentrated moving up the food chain. Marine mammals have on average 100 times greater levels of HBCD in their bodies than small aquatic organisms.

The chlorinated tris flame retardant TCPP is used in most polyurethane and polyisocyanurate insulation. HBCD and TCPP are global pollutants found in:

  • Environment and animals from the arctic to the antarctic
  • Soil, sediment, sewage sludge and landfill leachate
  • Indoor air and dust
  • Breast milk


Graph from data in Covaci 2006.

Facts: Flame retardant chemicals in building insulation

Building insulation materialFlame retardant estimated worldwide use for insulation (year)Health and environmental concernsPolicy actions

Expanded and extruded polystyrene (EPS and XPS)

HBCD (hexabromocyclododecane)

60 million pounds

27,000 metric tons


Endocrine disruption (thyroid hormones)

Neurodevelopmental effects

Aquatic toxicity


Recommended for global elimination by the Stockholm Convention

European Union: 2015 phaseout

Canada: 2016 phaseout

Polyurethane and polyisocyanurate (PIR)

TCPP (tris 1-chloro-2-propyl phosphate)

70 million pounds

32,000 metric tons


Potential carcinogenicity

Environmental persistence

Lack of data

European Union: regulated in toys under Toy Safety Directive

Under study at the U.S. Environmental Protection Agency and National Toxicology Program

Peer-reviewed paper: A case for re-evaluating building codes

Our interdisciplinary peer-reviewed paper, Flame retardants in building insulation: a case for re-evaluating building codes, explores the history, fire safety, health and environmental issues of flame retardants in building insulation. After extensive review of fire science studies, we concluded that flame retardants in building insulation do not provide a fire safety benefit for many applications.

We found that:

  • Since 1961, building codes have required foam plastic insulation materials to meet flame spread requirements as measured by the Steiner Tunnel test 
  • The Steiner Tunnel test does not accurately measure the flame spread of foam plastics
  • Flame retardants are added to foam plastic materials to pass the Steiner Tunnel test, but they do not provide fire safety benefits in many building applications
  • Fire safety for foam plastics is provided instead by code provisions requiring firestopping and thermal barriers

Read the full study, published in Building Research & Information
Read more on our blog


Picture shows the Steiner Tunnel test, which does not accurately measure the flame spread of materials which melt and drip like foam plastics. Photo: Intertek Testing Services, Inc.


For healthier, energy-efficient buildings, codes and standards need to be updated to reduce the use of harmful flame retardant chemicals while maintaining fire safety.

Code Change

Please visit to learn about our project to improve building codes for foam plastic insulation, the Safer Insulation Solution.


California Assembly Bill 127 (AB127) directs the State Fire Marshal to reexamine flammability standards for building insulation. Where the standards require addition of flame retardant chemicals without an increase in fire safety new flammability standards for building insulation may be proposed. These may provide manufacturers with flexibility in meeting the standards with or without the addition of chemical flame retardants and would be consistent with maintaining overall building fire safety.


U.S. Green Building Council’s Leadership in Energy & Environmental Design (LEED) Program awards points for not using halogenated flame retardants in buildings under Pilot Credit 54: Avoidance of Chemicals of Concern.

CBS Bay Area ConsumerWatch: East Bay lawmaker wants toxics out of insulation



Architects and Builders

Press: Healthy Buildings

SF Chronicle: Law may cut use of flame retardants in buildings

Gov. Jerry Brown has signed a law that may lead to a change in state building standards that would discourage the use of potentially hazardous flame-…

08 Oct 2013

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KQED Science: An environmental catch-22: fire safety chemicals in in…

Last year, Gov. Jerry Brown directed state agencies to reduce water use and greenhouse gas emissions through a green building action plan to “shrink the st…

26 Jun 2013

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CBS5 ConsumerWatch: East bay lawmaker wants toxics out of insulation

Assemblywoman Nancy Skinner of Berkeley is calling for a change in the state’s building code that would lessen the need for toxic chemicals in insulation. Julie Watts repo…

27 May 2013

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SFGate: S.F. ex-firefighter now battles cancer

Tony Stefani used to be a firefighter and a cancer patient. The two, he believes, had something to do with each other. Stefani was a firefighter i…

05 Feb 2013

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SFGate: Flame retardants may leach from your walls

Couches throughout the nation have become notorious for containing flame-retardant chemicals that may do more harm than good. Now, it turns out, t…

04 Feb 2013

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KQED Science: Flame retardants, redux: from toxic couches to buildin…

Speaking before a roomful of breast cancer researchers and activists in San Francisco earlier this month, Arlene Blum revealed her latest pla…

28 Nov 2012

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Scientific American blog: The environmental fallout of greener build…

Newer homes are remarkably energy tight thanks to superior insulating materials that are in wide circulation today. The energy savings can be substa…

28 Nov 2012

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Science Daily: Health and environmental risk in flame retardants in …

From Science Daily Researchers in the United States are calling for a change to the US building codes, following a study showing that the mandatory flame retardants r…

25 Nov 2012

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Washington Post: Concern grows over use of flame retardant HBCD

From the Washington Post Hexabromocyclododecane, commonly known as HBCD, is a flame retardant that is starting to give a lot of green builders headach…

04 Mar 2011

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Science & Policy Blog: Healthy Buildings

HBCD is on the way out – but use of questionable alternatives will p…

This week, the United States celebrates Thanksgiving. But internationally, countries that have signed the Stockholm Convention on Persistent Organic Pollutants have a dif…

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A new year, with promising new regulations

2013 was a productive year for fire safety and for environmental health! Two important regulatory changes that take effect this year have the power to reduce the use …

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USGBC honors leaders, unveils new building health initiative

The US Green Building Council Northern California Chapter’s annual Super Hero Awards gala, held last Tuesday in San Francisco, honored leaders in the nonprofit, education…

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HBCD alternatives assessment: narrow focus misses large problems

Polymeric flame retardant evaluated as HBCD alternative in Environmental Protection Agency’s Design for the Environment (EPA DfE) assessment presents unknown risks and po…

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World sees the light and bans HBCD. US stays in the dark.

In a historic decision, over 100 governments from around the world have agreed to list HBCD (hexabromocyclododecane) for global elimination. This ban means you can’t prod…

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New study: health and environmental risk in building insulation

Foam plastic insulation materials such as polystyrene, polyurethane, and polyisocyanurate are important to increase the energy efficiency of buildings and reduce carbon f…

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Presentations: Healthy Buildings

Flame Retardants in Furniture & Building Insulation Foams: Policies …

Speaker: Avery Lindeman Green Science Policy Institute, U.S. Event DIOXIN 2016 Date Sunday, August 28 - Friday, Septemb…

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Inventing Green Chemistry Alternatives to the “Six Classes” of Harmf…

Speaker: John Warner, PhD President, Warner Babcock Institute for Green Chemistry Event The Flame Retardant Dilemma and Beyo…

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Healthier Materials = Healthier Lives, the Next Chapter of Affordabl…

Speaker: Gina Ciganik Advisor of Housing Innovation at Healthy Building Network Event The Flame Retardant Dilemma and Beyond…

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A History of Thermal Insulation Regulations in California

Speaker: Justin Paddock, JD Chief, California Bureau of Electronic and Appliance Repair, Home Furnishings and Thermal Insulation (BEARHFTI) [toggle header="More about …

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What designers need: A restorative material economy

Speaker: Robin Guenther, Principal, Perkins + Will Event BIFMA Healthy Furniture Workshop: An Investigation into Stain-Repell…

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EWG action on stain-repellants and antimicrobials

Speaker: David Andrews, Senior Scientist, Environmental Working Group Event BIFMA Healthy Furniture Workshop: An Investigatio…

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Healthier Hospitals

Speaker: Tracey Eastbrooke, Environmental Health Director, Health Care Without Harm Event BIFMA Healthy Furniture Workshop: A…

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Chemical Management Policy Issues in China: Social and Economic Anal…

Speaker: Jianguo Liu, Ph.D., College of Environmental Sciences & Engineering, Peking University, Beijing, P. R. China Event S…

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We Built This City on HFRs: Initiatives to Reduce Flame Retardants i…

Speaker: Avery Lindeman, MSc, Deputy Director, Green Science Policy Institute Event Flame Retardant Dilemma Symposium Dat…

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Introduction to Life after TB117

Speaker: Arlene Blum, PhD Visiting Scholar, Chemistry, UC Berkeley, Green Science Policy Institute Event Green Science Polic…

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Sustainability Essentials: Fire Safety Without Harm

Speaker: Arlene Blum, PhD, Visiting Scholar, Chemistry, UC Berkeley, Green Science Policy Institute April 17, 2014 Webinar for the Sustainable Furnishings Council

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Healthy Buildings: Reducing the use of flame retardants and the "Si…

Speaker: Arlene Blum, PhD, Visiting Scholar, Chemistry, UC Berkeley, Green Science Policy Institute Event US Green Building C…

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