Healthy Buildings


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 Outdated flammability standards in building codes lead to the addition of flame retardant chemicals that are either known to be toxic or lack adequate health and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

Leave a Reply

Your email address will not be published. Required fields are marked *

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>