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The Environmental Fallout of Greener Buildings

The views expressed are those of the author and are not necessarily those of Scientific American.

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Newer homes are remarkably energy tight thanks to superior insulating materials that are in wide circulation today. The energy savings can be substantial – homeowners can use up to 60% less energy in the most efficient green homes. Now, a study published by a team of researchers in Building Research & Information makes it clear that the very materials that provide us with such energy efficiency are pumped full of harmful flame retardant chemicals. These chemicals, HBCD (hexabromocyclododecane) and TCPP (1-chloro-2-propyl) phosphate, are related to banned and phased-out substances like DDT, pentaBDE, and Tris. They are environmentally persistent, bioaccumulative, and are being manufactured at a frenetic pace without thought to how they might impact our environment and ultimately, our health.

The study focuses on foam insulation material: the spray-foam insulation you may have applied to fill a leaky attic as well as foam board insulation popular in green buildings for its excellent insulating properties. These materials are regularly treated with the flame retardants HBCD and TCPP to meet building standards for fire safety. But building codes do not specifically require the addition of flame retardants to foam insulation and the study shows that the presence of ½” thick drywall itself is enough to provide fire safety for many uses. So why are they being added at extra expense to manufacturers and unknown risk to us?

Two Types of Building Insulation

A local builder in my neighborhood shows off the environmentally friendly recycled newsprint insulation he has been working with since 2005 (right). But the city of Denver requires him to spray two inches of foam insulation (left) as a barrier in applications where there might be moisture. So much for being green.

Tens of millions of pounds of these flame retardant chemicals are being produced each year worldwide, with building insulation being the primary application. HBCD, the flame retardant added to polystyrene insulation, is currently being produced at a rate of 68 million pounds per year. Because of its highly bioaccumulative nature, HBCD is poised to become the 22nd chemical banned under the Stockholm Convention. In animal studies, it interferes with hormones and affects the developing nervous system.

The situation with TCPP isn’t any rosier. Data from the year 2000 in the EU shows it was being produced at a rate of 88 million pounds per year. Unlike HBCD, it tends to associate with water rather than fat and accumulates in the kidneys and liver. TCPP is found globally in groundwater, wastewater, and wildlife. Unfortunately, even if we completely stop production tomorrow, HBCD and TCPP will be a problem for decades to come; the similarly persistent pesticide DDT is still causing reproductive problems for the endangered California condor and can be found in every person tested by the CDC despite its being banned since 1972.

This alludes to a larger story about regulation and the power of industry. We tend to think that consumer products in this country are generally safe – surely someone is watching to ensure that they are not harmful to us or to the environment. A few areas, like pharmaceuticals, do benefit from government oversight to ensure companies are cautious and deliberate before bringing products to market. But for the vast majority of the products that are introduced to the public each year, there is no requirement that manufacturers prove what they’re peddling is not harmful, even if it contains substances that have known track records in animal studies or other equivalent evidence of toxicity. This industry-friendly approach is not the only model out there – it stands in sharp contrast to the EU’s Precationary Principle that places the burden of proof upon manufacturers to demonstrate a product is not harmful before distributing it for sale. Given the high stakes of such persistent environmental pollutants, it seems reckless to pump them into the environment with no long-term management plan, particularly since there are safer alternatives. At least in this one instance, our efforts to “green” up our energy consumption may be digging us deeper into a very different environmental hole.

The good news, as today’s study suggests, is that these chemicals are in many cases unnecessary additions to building insulation. They can safely be removed without affecting fire safety. So, for once, we can have it all: buildings that are safe, energy-efficient, and easy on the environment.


Worse Than Bedbugs, It’s the Couch Itself – on the Guest Blog by Kalliopi Monoyios
Infographic: Fire Safety Buzzkill – on Symbiartic by Kalliopi Monoyios

For More Information:

Safer Insulation Solution:

Kalliopi Monoyios About the Author: Kalliopi Monoyios is an independent science illustrator. She has illustrated several popular science books including Neil Shubin's Your Inner Fish and The Universe Within, and Jerry Coyne's Why Evolution is True. Find her at Follow on Twitter @symbiartic.

The views expressed are those of the author and are not necessarily those of Scientific American.

Comments 6 Comments

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  1. 1. drafter 4:14 pm 11/28/2012

    Building codes do require a flame spread index sample,
    California residential building code the 2010 CRC section R302.10. which is based on the International building code and the Uniform building codes. Therefore your article is incorrect in stating that there is no need for fireproofing insulation. A 1/2″ sheet rock will not suffice unless you enclose all insulation which would then require venting. I could go on but venting also raises other issues.
    Yes I’m a building designer.

    Link to this
  2. 2. Bops 8:24 pm 11/28/2012


    Are there other safer options?
    This is something that I don’t know anything about.
    There has to be other options.

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  3. 3. Bops 8:43 pm 11/28/2012

    Who ok’s these chemicals?
    Anyone who knowing harms millions of people with untested products for profit belongs in jail for wrongful deaths.

    Link to this
  4. 4. 1:43 pm 11/29/2012


    Check out the article cited ( I think you will find they are taking issue with the building codes and the tests used to determine the building codes:

    “Studies demonstrate that the Steiner Tunnel test does not give reliable fire safety results for foam plastic insulations. Foams that meet the Steiner Tunnel test still pose a fire hazard if used without a code-mandated thermal barrier. Insulations protected by a thermal barrier are fire safe and the use of flame retardants does not provide any additional benefit.”


    It is my understanding that there ARE safer alternatives that are not necessarily more expensive. The authors of the paper contend that in many cases the flame retardant chemicals are redundant – that is, other materials in use meet the fire safety criteria on their own, without need for added flame retardants. Aside from the Babrauskas et. al paper, I do believe there are other insulation materials that use safer flame retardants, but I have not researched it enough to provide a solid response.

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  5. 5. CR Herro 4:44 pm 12/3/2012

    I am concerned a blog with opinions was reprinted by Scientific American, and therefore could be construed as possessing appropriate technical merits.

    A few brief points to consider:

    • The ‘environmentally friendly’ insulation cited and photographed in the blog is cellulose, which requires the use of a large amount of Boric Acid and Sodium Borate as flame retardants, both of which are toxic.

    • The polyurethane spray foam also photographed uses an intumescing fire coating in the US to comply with the prescriptive fire code requirements. A brief review of associated MSDS and toxicology reports on intumescent paint show little to no toxic characteristics.

    • There are significant differences between the chemistry and associated fire retardants of polystyrene and polyurethane insulations discussed in the study. Once two different materials are grouping into ‘foam plastic’, you cannot then apply a singular toxicological assessment without generating fallacious statements.

    • Maintaining the status quo in insulation, as advocated in the blog, retains porous insulation that contributes to an excess of 1.2 trillion dollars of wasted energy (McKinsey Energy Study, 2009). The toxic emissions associated with these inefficiencies, from the various sources of energy consumed in the US, create a larger global impact than any hypothesized concerns raised in the study.

    I appreciate all investigation to improve the health of us and our build environment. A full Life Cycle Analysis of the toxic footprint of our status quo, energy efficiency impacts, and new components all need to be considered in order to define strategies to improve the indoor air quality and total toxic footprint of operating modern buildings. Too often, we cumulatively suffer from partial analysis and scare tactics.

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  6. 6. rmaccrea 12:58 pm 12/4/2012

    Scientific American should be better than the 11 o’clock news.

    Something must be said about the wrong conlcusion your headline makes. The article speaks about a serious threat from fire retardents in one type of insulation. It does not speak about the environemental fallout from greener buildings. Many will read this headline without reading the article. Its exaggerated claim will give them incorrect ammunition against green building. A more responsible way to report this serious issue might be:
    1. An energy efficient insulation should not be called green. Because fire retardents can be extremely hazardous, sprayfoam insulations should not use them in green projects.
    2. In our efforts to build green, we should be careful about which products we use. Some of them are very dangerous.
    I believe a well written headline can grab attention without sensationalizing with a wrong conclusion. Scientific American should be better than the 11 o’clock news.

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