How to buy a “quality” sofa – part 3 (foam)

4 09 2012

In an upholstered piece of furniture, the cushions need a filler of some kind.  Before plastics, our grandparents used feathers, horsehair or wool or cotton batting.  But with the advent of plastics, our lives changed.  You will now commonly see polyurethane foam, synthetic or natural latex rubber and the new, highly touted soy based foam.

In putting together this information on foams, I  leaned heavily on a series of blog postings by Len Laycock (CEO of Upholstery Arts), called “Killing Me Softly”.   It saddens me to have found out that Upholstery Arts is no longer selling furniture.

The most popular type of cushion filler today is polyurethane foam. Also known as “Polyfoam”, it has been the standard fill in most furniture since its wide scale introduction in the 1960’s because of its low cost (really cheap!).  A staggering 2.1 billion pounds of flexible polyurethane foam is produced every year in the US alone.[1]

Polyurethane foam is a by-product of the same process used to make petroleum from crude oil. It involves two main ingredients: polyols and diisocyanates:

  • A polyol is a substance created through a chemical reaction using methyloxirane (also called propylene oxide).
  • Toluene diisocyanate (TDI) is the most common isocyanate employed in polyurethane manufacturing, and is considered the ‘workhorse’ of flexible foam production.
    • Both methyloxirane and TDI have been formally identified as carcinogens by the State of California
    • Both are on the List of Toxic Substances under the Canadian Environmental Protection Act.
    • Propylene oxide and TDI are also among 216 chemicals that have been proven to cause mammary tumors. However, none of these chemicals have ever been regulated for their potential to induce breast cancer.

The US Environmental Protection Agency (EPA) considers polyurethane foam fabrication facilities potential major sources of several hazardous air pollutants including methylene chloride, toluene diisocyanate (TDI), and hydrogen cyanide.   There have been many cases of occupational exposure in factories (resulting in isocyanate-induced asthma, respiratory disease and death), but exposure isn’t limited to factories: The State of North Carolina forced the closure of a polyurethane manufacturing plant after local residents tested positive for TDI exposure and isocyanate exposure has been found at such places as public schools.

The United States Occupational Safety and Health Administration (OSHA) has yet to establish exposure limits on carcinogenicity for polyurethane foam. This does not mean, as Len Laycock explains, “that consumers are not exposed to hazardous air pollutants when using materials that contain polyurethane. Once upon a time, household dust was just a nuisance. Today, however, house dust represents a time capsule of all the chemicals that enter people’s homes. This includes particles created from the break down of polyurethane foam. From sofas and chairs, to shoes and carpet underlay, sources of polyurethane dust are plentiful. Organotin compounds are one of the chemical groups found in household dust that have been linked to polyurethane foam. Highly poisonous, even in small amounts, these compounds can disrupt hormonal and reproductive systems, and are toxic to the immune system. Early life exposure has been shown to disrupt brain development.”

“Since most people spend a majority of their time indoors, there is ample opportunity for frequent and prolonged exposure to the dust and its load of contaminants. And if the dust doesn’t get you, research also indicates that toluene, a known neurotoxin, off gases from polyurethane foam products.”

I found this on the Sovn blog:

“the average queen-sized polyurethane foam mattress covered in polyester fabric loses HALF its weight over ten years of use. Where does the weight go? Polyurethane oxidizes, and it creates “fluff” (dust) which is released into the air and eventually settles in and around your home and yes, you breathe in this dust. Some of the chemicals in use in these types of mattresses include formaldehyde, styrene, toluene di-isocyanate (TDI), antimony…the list goes on and on.”

Polyurethane foams are advertised as being recyclable, and most manufacturing scraps (i.e., post industrial) are virtually all recycled – yet the products from this waste have limited applications (such as carpet backing).  Post consumer, the product is difficult to recycle, and the sheer volume of scrap foam that is generated (mainly due to old cushions) is greater than the rate at which it can be recycled – so it  mostly ends up at the landfill.  This recycling claim only perpetuates the continued use of hazardous and carcinogenic chemicals.

Polyfoam has some hidden costs (other than the chemical “witch’s brew” described above):  besides its relatively innocuous tendency to break down rapidly, resulting in lumpy cushions, and its poor porosity (giving it a tendency to trap moisture which results in mold), it is also extremely flammable, and therein lies another rub!

Polyurethane foam is so flammable that it’s often referred to by fire marshals as “solid gasoline.” Therefore, flame-retardant chemicals are added to its production when it is used in mattresses and upholstered furniture.   This application of chemicals does not alleviate all concerns associated with its flammability, since polyurethane foam can release a number of toxic substances at different temperature stages. For example, at temperatures of about 800 degrees, polyurethane foam begins to rapidly decompose, releasing gases and compounds such as hydrogen cyanide, carbon monoxide, acetronitrile, acrylonitrile, pyridine, ethylene, ethane, propane, butadine, propinitrile, acetaldehyde, methylacrylonitrile, benzene, pyrrole, toluene, methyl pyridine, methyl cyanobenzene, naphthalene, quinoline, indene, and carbon dioxide. Of these chemicals, carbon monoxide and hydrogen cyanide are considered lethal. When breathed in, it deprives the body of oxygen, resulting in dizziness, headaches, weakness of the limbs, tightness in the chest, mental dullness, and finally a lapse of concsiousness that leads to death. Many of these are considered potential carcinogens or have been associated with a number of adverse health effects.

In conclusion, the benefits of polyfoam (low cost) must be evaluated with the disadvantages:  being made from a non-renewable resource (oil),  and the toxicity of main chemical components as well as the toxicity of the flame retardants added to the foam.

Natural or Synthetic latex: The word “latex” can be confusing for consumers, because it has been used to describe both natural and synthetic products interchangeably, without adequate explanation. This product can be 100% natural (natural latex) or 100% man-made (derived from petrochemicals) – or it can be a combination of the two – the so called “natural latex”.   Also, remember latex is rubber and rubber is latex.

  • Natural latex – The raw material for natural latex comes from a renewable resource – it is obtained from the sap of the Hevea Brasiliensis (rubber) tree, and was once widely used for cushioning.  Rubber trees are cultivated, mainly in South East Asia, through a new planting and replanting program by large scale plantation and small farmers to ensure a continuous sustainable supply of natural latex.  Natural latex is both recyclable and biodegradeable, and  is mold, mildew and dust mite resistant.  It is not highly flammable and does not require fire retardant chemicals to pass the Cal 117 test.  It has little or no off-gassing associated with it. Because natural rubber has high energy production costs (although a smaller footprint than either polyurethane or soy-based foams[2]),  and is restricted to a limited supply, it is more costly than petroleum based foam.
  • Synthetic latex – The terminology is very confusing, because synthetic latex is often referred to simply as “latex” or even “100% natural latex”.  It is also known as styrene-butadiene rubber  (SBR).   The chemical styrene is toxic to the lungs, liver, and brain.  Synthetic additives are added to achieve stabilization.    Often however, synthetic latex can be made of combinations of polyurethane and natural latex, or a combination of 70% natural latex and 30% SBR.  Most stores sell one of these versions under the term “natural latex” – so caveat emptor!  Being  petroleum based, the source of supply for the production of synthetic latex is certainly non-sustainable and diminishing as well.

Next I would like to talk about those new soy based foams that are all the rage, but I don’t want to bite off too much.   It’s a big topic and one that deserves its own post.   So that’s going to be next week’s post!

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5 responses

12 09 2012
Mark Hilliker

It should be said that polyfoams are a heavy contributor to toxic smoke in residential fires due to the presents of this material (in so many forms) in today’s homes. Most victims in home fires die form smoke not fire.

26 09 2012
Richelle Cavanagh

Please could you answer a question for me. After reading all the info on polyurethane foam and synthetic latex, I am confused about which product is deemed healthier. Would it be safer to purchase a bed for my daughter containing polyurethane foam or synthetic latex, which is less harmful to one’s health? I can’t find a stockist of natural latex in South Africa where I reside. Please advise.

26 09 2012
O Ecotextiles

Hi Richelle: I know it’s frustrating isn’t it? This is what we found about synthetic latex: “•Synthetic latex – The terminology is very confusing, because synthetic latex is often referred to simply as “latex” or even “100% natural latex”. It is also known as styrene-butadiene rubber (SBR). The chemical styrene is toxic to the lungs, liver, and brain. Synthetic additives are added to achieve stabilization. Often however, synthetic latex can be made of combinations of polyurethane and natural latex, or a combination of 70% natural latex and 30% SBR. Most stores sell one of these versions under the term “natural latex” – so caveat emptor! Being petroleum based, the source of supply for the production of synthetic latex is certainly non-sustainable and diminishing as well.” So I would try to determine how the synthetic latex was produced – is it SBR (not good!) or a combination of poly foam and natural latex? I would stay away from any combination of SBR/natural latex, since SBR is so toxic. Other options you might try (though I bet they’re expensive, but think of the long term consequences…) are horsehair, wool batting and perhaps down as a wrap. Down cushions can be surprisingly firm. A very thin mattress of wool and/or down might do the trick? Do any readers have suggestions?

13 12 2012
cntaylor27

Where can I buy quality natural latex to replace the foam in my sofa cushions? I have looked around and I feel that people either really love it or have horrible experiences. The two extremes. Any ideas?

13 12 2012
O Ecotextiles

I’m afraid I don’t have any leads for you – we only look into the issues and give you help in being able to evaluate manufacturer’s claims. I have seen various companies advertising latex which is Oeko Tex certified, and that would be a good start. As to quality issues, the company Latex International has lots of information on their website about what makes a “qualtiy” latex product.

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