Reducing Flame Retardants in Building Insulation to Protect Public Health

  • Date: Nov 03 2015
  • Policy Number: 20156

Key Words: Occupational Health And Safety, Environmental Health


All foam plastic building insulation in the United States contains flame-retardant chemicals that are known to be persistent and harmful to health or lack adequate toxicity information. The use of these insulation materials (polystyrene, polyurethane, and polyisocyanurate) is increasing as buildings become better insulated and more energy efficient. People are exposed to the flame retardants used in such insulation primarily as a result of manufacturing, installation, and disposal activities. These exposures represent a significant occupational and environmental hazard. Studies suggest that the use of flame retardants in foam plastic building insulation is not needed to ensure the fire safety of buildings, and building codes in Sweden and Norway have been updated to allow the safe use of insulation materials without flame retardants. Code authorities in the United States, including members of the International Code Council, should be encouraged to make similar updates to US codes to permit use of foam plastic insulation without flame retardants in cases in which fire safety can be maintained. This would greatly reduce the use of flame-retardant chemicals and their potential for human health and environmental harms. 

Relationship to Existing APHA Policy Statements

  • APHA Policy Statement 2004-05: Preventing Human Exposure to Polybrominated Diphenyl Ether (PBDE) Flame Retardants to Protect Public Health 
  • APHA Policy Statement 200019: PH Role of the Nat’l Fire Protection Assoc in Setting Codes and Standards for the Built Environment
  • APHA Policy Statement 200011: The Precautionary Principle and Children’s Health
  • APHA Policy Statement 9916: Public Health Role of Codes Regulating Design Construction and Use of Buildings
  • APHA Policy Statement 9304: Recognizing and Addressing the Environmental and Occupational Health Problems Posed by Chlorinated Organic Chemicals

Problem Statement 

Flame retardants in foam plastic building insulation: All foam plastic insulation in the United States contains added flame-retardant chemicals. Flame retardants in foam plastic building insulation are primarily organohalogens. Some flame retardants recently used in foam plastic insulation are not halogenated. However, no toxicological data are available to demonstrate the safety of these chemicals, and they continue to account for a negligible share of the market.

Flame retardants in foam plastic insulation have been detected widely in indoor and outdoor environments and are associated with adverse developmental effects, hormone disruption, liver toxicity, and other harms.[1–10] Hexabromocyclododecane (HBCD), used widely in polystyrene building insulation, is the 22nd chemical to be banned in more than 150 countries under Annex A of the Stockholm Convention on Persistent Organic Pollutants.[11] Although the United States is not a party to the Stockholm Convention, use of HBCD in the United States is expected to decrease.[12] The flame retardant being used in building insulation as a replacement for HBCD is a brominated styrene butadiene copolymer that is also persistent and has not been adequately evaluated for safety; the potential for adverse health effects from possible breakdown products or variations in manufacturing (e.g., lower molecular weight polymers) is not known.[13] Tris(1-chloro-2-propyl) phosphate (TCPP), the flame retardant commonly added to polyurethane and polyisocyanurate insulation materials, can accumulate in the liver and kidneys and affect nervous system development, and it is under study by the National Toxicology Program as a possible carcinogen. It is similar in structure to other known carcinogens.[14]

These chemicals are produced at levels of thousands of tons each year for use in foam plastic insulation, and production is increasing with growth in the construction market and with stricter requirements for building energy efficiency to mitigate carbon dioxide emissions and global climate change.[1] With this rising production and use, there is an increasing potential for exposures and for harm to public and occupational health throughout the life cycle of insulation (including production of flame retardants as well as production, installation, use, and disposal of insulation). A 2009 European Union report estimated that, when disposal is considered, building insulation accounts for about 87% of HBCD releases into the environment.[15] Total releases of HBCD from construction sites are estimated to exceed total releases from manufacturing and processing operations, suggesting that occupational exposures are of concern.[16] In addition, exposures among the general population may be underestimated and significant.[12] HBCD and TCPP have both been found in human breast milk, indicating exposures among pregnant and lactating women as well as babies and young children,[1,2,7] populations of unique concern.

Workers who manufacture or install these materials, or who demolish buildings, are routinely exposed to flame retardants in insulation and are not warned of the potential for long-term adverse health effects. In some cases, the flame retardants may be an undisclosed component of the insulation.[17] The National Institute for Occupational Safety and Health is currently conducting a study to better assess worksite exposures to flame retardants in spray foam plastic insulation.[18] Direct exposures to flame retardants from installed insulation should also be evaluated. Furthermore, firefighters and other populations may be adversely affected by combustion products from fires involving foam plastic insulation.[17]

U.S. building codes and use of flame retardants: The International Code Council publishes model building codes including the International Building Code (IBC) and the International Residential Code (IRC). These model codes form the basis of state and local building codes throughout the United States and are revised every three years. Their intent is to protect the public and first responders from fire and other hazards. The codes require foam plastic insulation, which is affordable and efficient but flammable, to meet certain flammability standards. Industry typically meets these standards by adding the halogenated flame-retardant chemicals discussed above to insulation. In most cases, the codes also require foam plastic insulation to be protected from fire by gypsum wallboard or a similar barrier material.[1] The US Department of Housing and Urban Development has similar requirements for foam plastic insulation used in manufactured housing.[19]

A review of the existing literature indicates that fire safety can be maintained while reducing use of flame-retardant chemicals in building insulation materials.[20–22] This reduction could be achieved by updating building codes so that flammability testing is not required when it is not needed to achieve fire safety. There is strong opposition to such updates in the building codes from producers of flame retardants and affiliated industry groups, possibly owing to concerns about potential loss of market share and a perceived increase in liability among insulation manufacturers.

Such updates would increase consumers’ choice of insulation materials, thereby benefitting the insulation market, a subset of the chemical industry. This could offset industry losses from reduced use of flame retardants in some foam plastic insulation materials. Updates to flammability test requirements are not expected to result in increased construction costs. 

The economic costs of the harms, especially to the health of children and workers, resulting from use of these chemicals in foam plastic insulation are difficult to quantify.

Unless building codes are updated to allow for the safe use of foam plastic insulation without flame retardants, harmful and potentially harmful flame retardants will continue to be used. This situation poses an unacceptable risk to workers and fire service professionals; it also is an environmental justice issue owing to the environmental release of flame retardants and toxic combustion products such as halogenated dioxins and furans during the disposal or recycling stage of the product life cycle.[1,23–35] Low-income communities located near landfills and incineration facilities are the most vulnerable to, and historically the most affected by, exposures to harmful chemicals in waste products. 

Updating codes to ensure fire safety and benefit public and worker health: Foam plastics can be used safely in buildings when they are protected from fire by concrete, masonry, gypsum wallboard, or comparable materials.[1] US fire data indicate that foam plastic insulation materials properly installed behind such barriers do not pose a significant fire hazard.[36] Furthermore, a comparison of different foam plastic insulation materials demonstrates that the current flammability test requirements in building codes do not reliably improve the fire behavior of unprotected foam plastic insulation.[1,37,38] 

As a result of concern about the toxicity and persistence of flame retardants used in building insulation, Sweden and Norway have both adopted building codes that allow safe use of foam plastic insulation without added flame-retardant chemicals.[8,20–22] There is no evidence of increased fire incidence or losses, either in finished construction or on job sites, since the implementation of these changes.[8] US building code requirements for foam plastic insulation materials should be similarly updated to provide fire safety in buildings without needlessly exposing workers and the public to harmful or potentially harmful flame retardants. Currently, San Francisco, New York City, and the state of California are discussing such modifications to local codes. Other state and local authorities should also consider such changes, which could be enacted on a shorter time scale than changes at the IBC or IRC level and would provide support for proposals to update the IBC and the IRC.

There has historically been inadequate inclusion of public health considerations in regulatory and standard-making activities. Public health professionals and related public interest groups are underrepresented in many standard-making and regulatory bodies, even though the decisions of these groups routinely have implications for public health.  

Public health groups have previously urged decision makers to employ alternative design solutions in order to minimize or avoid the use of chemicals known or strongly suspected to cause harm. They have also supported pollution prevention through consideration of safer alternatives. Such interventions are now needed to address the issue of flame retardants in foam plastic building insulation.

Evidence-Based Strategies to Address the Problem 

The International Code Council should update flammability requirements for foam plastic insulation to allow for its safe use without flame-retardant chemicals. Instances where such materials can be used safely without added flame retardants include uses below grade (where insulation is protected by concrete, dirt, and other nonburning materials) or cases in which the materials are protected behind a thermal barrier material fire-stopped gypsum board. Foam plastic insulation cannot meet current code requirements without the addition of flame-retardant chemicals.[1] Thus, to reduce use of these harmful and unneeded flame retardants, building codes must be updated. In addition to supporting updates to model building codes, state and local jurisdictions could implement their own updated standards on a shorter time scale.

When Sweden and Norway updated their building code requirements, production of insulation containing HBCD for domestic use ceased.[39] In the United States, reductions in foam plastic insulation containing flame retardants would result in large public and worker health benefits by reducing human and environmental exposure to hazardous flame retardants as well as their harmful breakdown and combustion by-products, such as halogenated dioxins and furans.

In the United States, upholstered furniture can be considered as an analogous case. An outdated and ineffective flammability standard, California’s Technical Bulletin 117 (TB117), led to the use of PBDEs and other harmful flame retardant chemicals at significant levels in the foam filling of home furniture throughout the United States for decades.[31] When this standard was updated in 2013, manufacturers began to produce upholstered furniture without added flame retardants. More and more manufacturers are choosing to meet the new flammability standard, Technical Bulletin 117-2013, without using flame retardants.[40] This is expected to result in decreased human exposures to the harmful flame-retardant chemicals previously used in home furnishings. The new standard is expected to maintain or modestly improve fire safety.

Opposing Arguments/Evidence

Some entities believe that flammability standards for foam plastic insulation cannot be changed safely. Their arguments against such an update include concerns that foam plastic insulation without flame retardants (1) represents a greater fire hazard during transportation, (2) represents a greater fire hazard in storage facilities and at worksites, and (3) will be used in ways that do not comply with building codes and could therefore result in reduced fire safety once installed.

Concerns about the fire safety of these materials during storage and transportation or on construction sites are unsurprising: historically, foam plastics that were not properly protected from ignition have been involved in significant fires. However, foam plastic insulation without flame retardants represents a manageable risk on construction sites and during transportation.[1] Norway provides a proof of concept, in that there has been no increase in accidental fires in Norway involving polystyrene (geofoam) insulation since 2004, when codes were changed and those materials began to be manufactured and used without flame retardants.[8]

In the United States, there are other codes and standards, including the International Fire Code and Occupational Safety and Health Administration regulations, that prescribe necessary safety measures for storage and safe handling of flammable materials. It is important to follow these practices to ensure fire safety, whether or not foam plastic insulation contains flame retardants: both types of foam plastic involve similar fire hazards if exposed. There are currently no additional regulations for the safe transportation of foam plastics without flame retardants. Food-grade polystyrene, for instance, is transported in bulk and has not been identified as a safety concern. 

Building codes already require clear labeling of insulation materials to indicate compliance with relevant code sections and standards and to enable proper use and installation in accordance with code provisions. Industry should be able to develop a product labeling scheme in line with current practices to indicate whether foam plastic insulation contains or does not contain added flame retardants and instances in which such insulation can be used safely. Contractors are also equipped to deal with thousands of different products at job sites, and increasing the varieties of insulation on site to include materials without flame retardants would not add significant challenges. 

While the addition of flame retardants may provide slightly increased resistance to ignition from certain ignition sources, there is no meaningful difference in fire behavior of foam plastic insulation with or without flame retardants when ignited by other ignition sources or once a fire is under way; thus, potential use of these materials for applications other than those allowed by code is not expected to significantly increase the fire hazard associated with installed foam plastic building insulation.

Flame-retardant chemicals are not the only health and environmental drawback of foam plastic insulation: for instance, isocyanates are a recognized health hazard among installers of spray foam insulation.[17] For this reason, some groups question the benefit of updating flammability standards for foam plastic insulation materials because doing so addresses only the health hazards related to flame retardants. These groups suggest that, rather than updating flammability standards, it would be better to promote use of alternative insulation materials such as rockwool or plant-based insulations. We agree that such alternative materials can be used to reduce hazards to workers and the environment. However, most alternative insulation materials are currently cost prohibitive for many construction projects. Furthermore, alternative insulation materials do not have the necessary physical properties to be used in many applications (e.g., under concrete slabs and in contact with the soil). Foam plastic is currently the most affordable and efficient insulation material and will likely continue to be used widely, even if alternative insulation materials become more affordable and common. It is therefore important to update flammability requirements so that these materials can be used safely without harmful flame retardants. These updates would not require a change in current construction practices and are not expected to increase the cost of foam plastic insulation.

Insulation materials play an important role in reducing energy use. In a typical home, heating and cooling can account for 50% to 70% of energy costs; better insulating existing and new buildings can lead to dramatic reductions in the amount of energy used for heating and cooling.[41] It is important that insulation continue to be used for climate change mitigation, despite the health and ecological effects of flame retardants. 

Alternative Strategies 

United States chemical regulations, including the 1976 Toxic Substances Control Act (TSCA) administered by the Environmental Protection Agency (EPA), could potentially reduce the use of toxic or unsafe flame retardants in foam plastic building insulation. Revisions to and updates of the TSCA are currently being discussed in the US Congress and may be implemented in the coming years, which could improve the EPA’s authority to restrict use of hazardous substances. However, the EPA has not historically been able to ensure use of only safe chemicals in insulation as well as many other products. It is not uncommon for a harmful chemical to be used for years or decades before there are adequate data to restrict its use. When a chemical known to be harmful is banned or phased out, it is often replaced by a chemical with similar characteristics that has not yet been adequately studied. Such “regrettable substitutions” (when a banned chemical is substituted with a similarly harmful one) can be best avoided by changes to codes, standards, or policies that drive the use of the harmful chemical in the first place. 

Action Steps 

  1. Public health advocates should help educate union members and other construction and industrial workers, fire safety professionals, government agencies, and the general public about the health and ecological hazards of flame retardants in foam plastic insulation.
  2. Thorough toxicological testing should be required for all flame-retardant chemicals prior to their use in insulation to ensure that they are safe for human and ecological health. This testing should include consideration of endocrine disruption and other long-term effects resulting from exposure to environmentally relevant levels of these chemicals.
  3. Product manufacturers should comply with flammability requirements without the use of added flame retardants whenever possible. When flame retardants are used, manufacturers should select the safest flame retardant and should avoid flame retardants that are persistent, bioaccumulative, and/or toxic.
  4. Federal, state, and local governments should adopt policies encouraging safe disposal or reuse of insulation containing harmful flame-retardant chemicals. 
  5. State and local governments should consider updates to codes and regulations in their jurisdiction that would protect public health by allowing for reduced use of harmful flame retardants. Such updates could include changes in flammability requirements for specific uses of foam plastic insulation in instances in which fire safety can be maintained without flame retardants.
  6. The fire safety community and members of standard-making bodies such as the International Code Council should consider proven and potential adverse health effects of flame-retardant chemicals that may be used to meet flammability requirements in their decision-making processes. 
  7. Participants in the International Code Council code development process should approve proposals to update flammability requirements to allow for decreased use of flame-retardant chemicals when fire safety will be maintained. These proposals may be submitted during the normal code revision cycle, which takes place once every three years. State and local code authorities should provide support for these proposals when possible.


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