What is intrinsically flame retardant polyester?

11 02 2014

Polyester is the terminal product in a chain of very reactive and toxic precursors. Most are carcinogens; all are poisonous. And even if none of these chemicals remain entrapped in the final polyester structure (I don’t know enough chemistry to figure that one out – can anybody help?), the manufacturing process requires workers and our environment to be exposed to some or all of these toxic precursors. ( To see our blog post about polyester, click here ).  So I’m just not a fan of synthetics – even polyester.  Just so you know.

To make an intrinsically flame retardant polyester,  the most common method is to add  brominated flame retardants (BFR’s)  to the polymer during the melt phase.   This means the chemicals are “trapped” in the polymer.  Included in this huge class of BFR’s is:

  • Polybrominated diphenyl ethers (PBDE’s):  besides PBDE, the group includes DecaBDE, OctaBDE and PentaBDE (neither Octa nor Penta is manufactured anymore)
  • Polybrominated biphenyls (PBB) – also not manufactured anymore
  • Brominated cyclohydrocarbons

Brominated flame retardants are persistent, accumulate in the food chain, and toxic to both humans and the environment and are suspected of causing neurobehavioral effects, endocrine disruption,  cancer and other degenerative diseases.

So now you have a polyester fabric which is made from toxic monomers, which in turn come from crude oil, a precious non-renewable resource. It becomes  “intrinsically flame retarded” by having PBDE’s mixed into the polymer at the melt stage.  Personally, I wouldn’t want to live with that mixture.  Think about it:  It’s generally assumed that PBDE’s in plastics (of all kinds)  volatilize –  but even if they didn’t, each time you sit on your sofa microscopic particles of the fabric are abraded and fall into the dust in your homes, where you can breathe them in.

Many manufacturers advertise the use of “intrinsically flame retardant” polyester fabrics on their sofas.  But why would you need an intrinsically flame retarded fabric on a sofa in your home?  There is no law that says the fabric in a residential setting must have flame retardants (unlike the laws that exist to cover public areas, like offices, airports, hotels, etc.)  Can’t you use a fabric without flame retardants?

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What does “eco friendly” vinyl mean?

28 01 2014

Polyvinyl chloride – PVC – is the most toxic plastic for our health and it’s not so good for the environment either.  First, it’s made from petroleum, one of our scarce natural resources.   Globally, over 50% of PVC manufactured is used in construction, in products such as pipelines, wiring, siding, flooring and wallpaper – as well as a host of other products, including fabrics.   As a building material PVC is cheap, easy to install and easy to replace. PVC is replacing ‘traditional’ building materials such as wood, concrete and clay in many areas. Although it appears to be the ideal building material, PVC has high environmental and human health costs that its manufacturers fail to tell consumers.

From its manufacture to its disposal, PVC emits toxic compounds. During the manufacture of the building block ingredients of PVC (such as the vinyl chloride monomer) dioxin and other persistent pollutants are emitted into the air, water and land, which present both acute and chronic health hazards. During use, PVC products can leach toxic additives, for example flooring can release softeners called phthalates. When PVC reaches the end of its useful life,  it cannot be recycled, so it must either  be landfilled, where it leaches toxic additives, or incinerated, again emitting dioxin and heavy metals. When PVC burns in accidental fires, hydrogen chloride gas and dioxin are formed.

No other plastic contains or releases as many dangerous chemicals. There’s no safe way to manufacture, use or dispose of PVC products.

eco-friendly_vinyl-459x459 copyAnd yet we see the advertisement of “eco friendly” vinyl.  What does it mean?

Vinyl is commonly used as a shorthand name for PVC.  Usually, when a product is referred to as “vinyl,” it is comprised primarily of PVC. Occasionally it also may refer to polyvinylidene chloride (PVDC) a closely related compound, which is used in food wraps (‘Saran’) and other films.  This product shares most of the same environmental health problems with PVC.

In chemistry, however, the term “vinyl’ actually has a broader meaning, encompassing a range of different thermoplastic chemical compounds derived from ethylene. In addition to PVC, “vinyls” in building materials also include:

  1. ethylene vinyl acetate (EVA), used in films, wire coating and adhesives
  2. polyethylene vinyl acetate (PEVA) a copolymer of polyethylene and EVA used in shower curtains, body bags
  3. polyvinyl acetate (PVA), used in paints and adhesives, such as white glue, and
  4. polyvinyl butyral (PVB), used in safety glass films.

What makes PVC different from the other vinyls is the addition of a chlorine molecule (The “C” in PVC and PVDC stands for chlorine).  Chlorine is the source of many of the concerns with PVC, such as the generation of dioxin, a highly carcinogenic chemical produced in both the manufacture and disposal of PVC. Due to its persistent and bioaccumulative nature (it travels long distances without breaking down and concentrates as it moves up the food chain to humans) dioxin has become a global problem and an international treaty – the Stockholm Convention on persistent organic pollutants (POPs) – now prioritizes the elimination of processes that produce dioxin.

Some of the non-chlorinated vinyls (EVA, PEVA, PVA and PVB) are now beginning to be used as direct substitutes for PVC. EVA has been in use for several years as a chlorine free substitute for PVC – primarily in non building materials like toys and athletic shoes, but occasionally as a protective film or binder. In the building industry, post-consumer recycled PVB is now beginning to be used to replace PVC in carpet backing. Absence of chlorine alone does not make these other vinyls the final answer in the search for green polymers. There are still plenty of toxic challenges and untested chemicals in the life cycle of any petrochemical product. As is the case with most other polymers competing with PVC, however, the weight of available evidence indicates that the absence of chlorine in the formula will generally render the lifecycle environmental health impacts of PVB and the other vinyls less harmful than PVC – and initial study is bearing this out. Like the polyolefin plastics, the use of PVB and the other non-chlorinated vinyls represents a step forward in the search for alternatives to PVC.

In summary, with the exception of paints, glues and certain films, “vinyl” as a product description almost always means made of PVC. The term vinyl in ethylene vinyl acetate (EVA), polyethylene vinyl acetate (PEVA), polyvinyl acetate (PVA), and polyvinyl butyral (PVB), however, does not refer to PVC and does not raise the same concerns associated with chlorinated molecules like PVC.

When in doubt about the use of the term “vinyl”, ask if it is PVC.

For virtually all PVC applications, safer alternatives exist, using more sustainable, traditional materials – such as paper, wood or local materials. PVC can also be replaced by a variety of other, less environmentally damaging plastics, although most plastics pose some risk to the environment and contribute to the global waste crisis.





What kind of fabric for your new sofa?

26 09 2013

We’ve looked at the frame, suspension system and cushioning on a sofa;  next up:  fabric.  We consider fabric to be a very important, yet certainly misunderstood, component of furniture.  It can make up 40 – 45% of the price of a sofa.    So we’ll be breaking this topic up into several smaller bite size portions:  after a general discussion of what kind of fabric to choose for your lifestyle,  we’ll look at the embodied energy in your fabric choice, and then why an organic fabric is better for you as well as the rest of us.

One thing to remember is that there is much  more fabric used in constructing an  upholstered piece of furniture than just the decorative fabric that you see covering the piece – a typical “quality” sofa also uses about 20 yards of decorative fabric, plus 20 yds of lining fabric, 15 yds of burlap and 10 yds of muslin, for a total of 65 yards of fabric!

So what do people look for in an upholstery fabric?

After color, fabric durability is probably top of everybody’s list.  Durability translates into most people’s minds as “heft” – in other words, a lightweight cotton doesn’t usually come to mind.  A fabric with densely woven yarns tends to be more durable than a loosely woven fabric.  Often people assume leather is the best choice for a busy family.  We did a post about leather – if you’re at all considering leather, please read this first (https://oecotextiles.wordpress.com/2012/05/22/leather-furniture-what-are-you-buying/ ).  Another choice  widely touted is to use Ultrasuede.  Please see our post about this fabric: https://oecotextiles.wordpress.com/2010/09/08/is-ultrasuede%c2%ae-a-green-fabric/.

Equally important in evaluating durability as the weight of the fabric is the length of the fibers.  Cotton as a fiber is much softer and of shorter lengths than either hemp or linen, averaging 0.79 -1.30 inches in length.  Hemp’s average length is 8 inches, but can range up to 180 inches in length. In a study done by Tallant et. al. of the Southern Regional Research Laboratory,  “results indicate that increases in shortfibers are detrimental to virtually all yarn and fabric properties and require increased roving twist for efficient drafting during spinning. A 1% increase in fibers shorter than 3/8 in. causes a strength loss in yarns of somewhat more than 1%.”[1]    In fact, the US textile industry has  advocated obtaining the Short Fiber Content (SFC) for cotton classification.  SFC is defined as the percentage of fibers shorter than ½ inch.  So a lower cost sofa upholstered in cotton fabric, even one identified as an upholstery fabric, could have been woven of short fiber cotton, a cheaper alternative to longer fiber cotton and one which is inherently less durable – no matter how durable it appears on the showroom floor.

Patagonia, the California manufacturer of outdoor apparel, has conducted  tests on both hemp and other natural fibers, with the results showing that hemp has eight times the tensile strength and four times the durability of other natural fibers.   Ecolution had a hemp twill fabric tested for tensile and tear strength, and compared the results with a 12-oz cotton denim.  Hemp beat cotton every time:   Overall, the 100% hemp fabric had 62% greater tear strength and 102% greater tensile strength. [2]   And polyester trumps them both – but that’s a whole different ballgame, and we’ll get to that eventually.

There is a high correlation between fiber strength and yarn strength.  People have used silk as an upholstery fabric for hundreds of years, and often the silk fabric is quite lightweight;  but silk is a very strong fiber.

In addition to the fiber used, yarns are given a twist to add strength. This is called Twist Per Inch or Meter (TPI or TPM) – a tighter twist (or more turns per inch) generally gives more strength.  These yarns are generally smooth and dense.

So that brings us to weave structure.  Weave structures get very complicated, and we can refer you to lots of references for those so inclined  to do more research (see references listed at the end of the post).

But knowing the fibers, yarn and weave construction still doesn’t answer people’s questions – they want some kind of objective measurement.  So in order to objectively compare fabrics,  tests to determine wear were developed (called abrasion tests), and many people today refer to these test results as a way to measure fabric durability.

Abrasion test results are supposed to forecast how well a fabric will stand up to wear and tear in upholstery applications.  There are two tests generally used:  Martindale  and Wyzenbeek (WZ).  Martindale is the preferred test in Europe; Wyzenbeek is preferred in the United States.  There is no correlation between the two tests, so it’s not possible to estimate the number of cycles that would be achieved on one test if the other were known:

  • Wyzenbeek (ASTM D4157-02):  a piece of cotton duck  fabric or wire mesh is rubbed in a straight back and forth motion on a      piece of fabric until “noticeable wear” or thread break is evident.  One back and forth motion is called a “double rub” (sometimes written as “dbl rub”).
  • Martindale (ASTM D4966-98):  the abradant in this test is worsted wool or wire screen, the fabric specimen is a circle or round      shape, and the rubbing is done in a figure 8, and not in a straight line as in Wyzenbeek.  One circle 8 is a cycle.

The Association for Contract Textiles performance guidelines lists the following test results as being suitable for commercial fabrics:

Wyzenbeek Martindale
General contract 15,000 20,000
Heavy duty contract 30,000 40,000

According to the Association for Contract Textiles, end use examples of “heavy duty contract” where 30,000 WZ results should be appropriate are single shift corporate offices, hotel rooms, conference rooms and dining areas.  Areas which would require higher than 30,000 WZ are: 24 hour facilities (like transportation terminals, healthcare emergency rooms, casino gambling areas,  and telemarketing offices) and theatres, stadiums, lecture halls and fast food restaurants.

Sina Pearson, the textile designer, has been quoted in the Philadelphia Inquirer as saying that 6,000 rubs (Wyzenbeek) may be “just fine” for residential use”[3]   The web site for Vivavi furniture gives these ratings for residential use:

Wyzenbeek
from to
Light use 6,000 9,000
Medium use 9,000 15,000
Heavy use 15,000 30,000
Maximum use >30,000

Theoretically, the higher the rating (from either test) the more durable the fabric is purported to be.  It’s not unusual for designers today to ask for 100,000 WZ results.  Is this because we think more is always better?  Does a test of 1,000,000 WZ guarantee that your fabric will survive years longer than one rated only 100,000 WZ?  Maripaul Yates, in her guidebook for interior designers, says that “test results are so unreliable and the margin of error is so great that its competency as a predictor of actual wear is questionable.”[4]  The Association for Contract Textiles website states that “double rubs exceeding 100,000 are not meaningful in providing additional value in use.  Higher abrasion resistance does not necessarily indicate a significant extension of the service life of the fabric.”

There are, apparently, many ways to tweak test results. We’ve been told if we don’t like the test results from one lab, we can try Lab X, where the results tend to be better.  The reasons that these tests produce inconsistent results are:

1. Variation in test methods:       Measuring the resistance to abrasion is very complex.  Test results are affected by many factors that include the properties and dimensions of  the fibers; the structure of the yarns; the construction of the fabrics;  the type, kind and amount of treatments added to the fibers, yarns, or fabric; the time elapsed since the abradant was changed;  the type of  abradant used; the tension of the specimen being tested,the pressure between the abradant and the specimen…and other variables.

2. Subjectivity:    The  measurement of the relative amount of abrasion can be affected by the method of evaluation and is often influenced by the judgment of the operator.  Cycles to rupture, color change, appearance change and so forth are highly variable parameters and subjective.

3. Games Playing:     Then there is, frankly, dishonest collusion between the tester and the testee.  There are lots of games that are played. For instance, in Wyzenbeek, the abradant, either cotton duck or a metal screen, must be replaced every million double rubs. If your fabric is tested at the beginning of that abradant’s life versus the end of its life, well.. you can see the games. Also, how much tension the subject fabric is under –  the “pull” of the stationary anchor of the subject fabric, affects the  rating.

In the final analysis, if you have doubts about the durability of a fabric,  will any number of test results convince you otherwise?  Also, if your heart is set on a silk  jacquard, for example, I bet it would take a lot of data to sway you from your heart’s desire.  Some variables just trump the raw data.

REFERENCES FOR WEAVE STRUCTURE:

1.  Peirce, F.T., The Geometry of Cloth Structure, “The Journal of the Textile Institute”, 1937: pp. 45 – 196

2. Brierley, S. Cloth Settings Reconsidered The Textile Manufacturer 79 1952: pp. 349 – 351.

3. Milašius, V. An Integrated Structure Factor for Woven Fabrics, Part I: Estimation of the Weave The Journal of the Textile Institute 91 Part 1 No. 2 2000: pp. 268 – 276.

4. Kumpikaitė, E., Sviderskytė, A. The Influence of Woven Fabric Structure on the Woven Fabric Strength Materials Science (Medžiagotyra) 12 (2) 2006: pp. 162 – 166.

5. Frydrych, I., Dziworska, G., Matusiak, M. Influence of Yarn Properties on the Strength Properties of Plain Fabric Fibres and Textile in Eastern Europe 4 2000: pp. 42 – 45.

6. ISO 13934-1, Textiles – Tensile properties of fabrics – Part 1: Determination of Maximum Force and Elongation at Maximum Force using the Strip Method, 1999, pp. 16.


[1] Tallant, John, Fiori, Louis and Lagendre, Dorothy, “The Effect of the Short Fibers in a Cotton on its Processing Efficiency and Product Quality”, Textile Research Journal, Vol 29, No. 9, 687-695 (1959)

[2]  http://www.globalhemp.com/Archives/Magazines/historic_fiber_remains.html

[3] ‘How will Performance Fabrics Behave”, Home & Design,  The Philadelphia Inquirer, April 11, 2008.

[4] Yates, Maripaul, “Fabrics: A Guide for Interior Designers and Architects”, WW. Norton and Company.





Sofa cushions – foam, soy foam or latex?

12 09 2013

So we have produced the frame and put in the suspension system.  Next in line are the cushions – something soft to sit on.

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.  Polyurethane foam was introduced as a cushion component in furniture in 1957 –  only a bit more than 50 years ago – and quickly replaced latex, excelsior, cotton batting, horsehair and wool because it was CHEAP!  Imagine – polyfoam cushions at $2 vs. natural latex at $7 or $8.  Price made all the difference.  Today, Eisenberg Upholstery’s website says that “easily 25% of all furniture repairs I see deal with bad foam or padding. The point is start with good foam and you won’t be sorry.”

Cushions are generally measured by two values:

  • The density or weight per cubic foot of polyurethane foam. The higher the number the more it weighs.   Foam that has a density of 1.8 foam, for example, contains 1.8 lbs of foam per cubic foot and foam that is 2.5 foam would have 2.5 lbs of foam per cubic foot.  Density for sofa cushions ranges between 1.6 and 5 or even 6.
  • The second measurement tells you the firmness of the foam  (called the IFD  – the Indentation Force Deflection). The IFD is the feel of the cushion, and tells you how much weight it takes to compress the foam by one third. The lower IFD will sit softer. The higher IFD will sit firmer.  IFD numbers range between 15 to 35

What many people don’t realize is that the density and firmness numbers go hand in hand – you can’t look at one without the other.  They are expressed as density/firmness, for example: 15/30 or 29/52.  The first, 15/30 means that 1.5 pounds of foam per cubic foot will take 30 pounds of weight to compress the foam 33%.  The second example means that 2.9 pounds per cubic foot of foam will take 52 pounds of weight to compress the block one third.

The foam is then wrapped with something to soften the edges – for example,  Dacron or polyester batting, cotton or wool batting or down/feathers.

Lowest quality sofas will not even wrap the (low quality) foam; higher quality sofas have cushions that are made from very high quality foam and wrapped in wool or down.  But as you will see, the foam is itself very problematic.

You will now commonly find in the market polyurethane foam, synthetic or natural latex rubber and the new, highly touted soy based foam.  We’ll look at these individually, and explore issues other than embodied energy :

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 in his series “Killing You Softly”, “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.” When untreated foam is ignited, it burns extremely fast. Ignited polyurethane foam sofas can reach temperatures over 1400 degrees Fahrenheit within minutes. Making it even more deadly are the toxic gasses produced by burning polyurethane foam –  such as hydrogen cyanide. The gas was also implicated in the 2003 Rhode Island nightclub fire that killed 100 people, including Great White guitarist Ty Longley, and injured more than 200 others. Tellingly, a witness to that fire, television news cameraman Brian Butler, told interviewers that “It had to be two minutes, tops, before the whole place was black smoke.”   Just one breath of superheated toxic gas can incapacitate a person, preventing escape from a burning structure.

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 releases 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.

According to the federal government’s National Institute of Standards and Technology, polyurethane foam in furniture is responsible for 30 percent of U.S. deaths from fires each year.

In conclusion, the benefits of polyfoam (low cost) is far outweighed by 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 – not to mention the fact that even the best foams begin to break down after around 10 – 12 years of “normal use”.[2]

Now we see ads for a  new miracle product: a bio based foam made from soybeans, which is highly touted as “A leap forward in foam technology, conserving increasingly scarce oil resources while substituting more sustainable options,” as one product brochure describes it. Companies and media releases claim that using soy in polyurethane foam production results in fewer greenhouse gas emissions, requires less energy, and could significantly reduce reliance on petroleum. Many companies are jumping on the bandwagon, advertising their green program of using foam cushions with “20% bio based foam” (everybody knows we have to start somewhere and that’s a start, right?).  As Len Laycock,  CEO of Upholstery Arts (which was the first furniture company in the world to introduce Cradle to Cradle product cycle and achieve the Rainforest Alliance Forest Stewardship Council Certification),  says  – who wouldn’t sleep sounder with such promising news?   (I have leaned heavily on Mr. Laycock’s articles on poly and soy foam, “Killing You Softly”, for this post.)

As with so many over hyped ‘green’ claims, it’s the things they don’t say that matter most.  While these claims contain grains of truth, they are a far cry from the whole truth. So called ‘soy foam’ is hardly the dreamy green product that manufacturers and suppliers want people to believe.

To begin, let’s look at why they claim soy foam is green:

  1. it’s made from soybeans, a renewable  resource
  2. it reduces our dependence on fossil  fuels  by  both reducing the amount of fossil fuel needed for      the feedstock  and  by reducing the energy requirements needed to produce the foam.

Are these viable claims?

It’s made from soybeans, a renewable resource:  This claim is undeniably true.   But what they don’t tell you is that this product, marketed as soy or bio-based,  contains very little soy. In fact, it is more accurate to call it ‘polyurethane based foam with a touch of soy added for marketing purposes’. For example, a product marketed as “20% soy based” may sound impressive, but what this typically means is that only 20 % of the polyol portion of the foam is derived from soy. Given that polyurethane foam is made by combining two main ingredients—a polyol and an isocyanate—in approximately equal parts, “20% soy based” translates to a mere 10% of the foam’s total volume. In this example the product remains 90% polyurethane foam and by any reasonable measure cannot legitimately be described as ‘based’ on soy. If you go to Starbucks and buy a 20 oz coffee and add 2-3 soy milk/creamers to it, does it become “soy-based” coffee?

It reduces our dependence on fossil fuels: According to Cargill, a multi-national producer of agricultural and industrial products, including BiOH polyol (the “soy” portion of “soy foam”), the soy based portion of so called ‘soy foam’ ranges from  5% up to a theoretical 40% of polyurethane foam formulations. This means that while suppliers may claim that ‘bio foams’ are based on renewable materials such as soy, in reality a whopping 90 to 95%, and sometimes more of the product consists of the same old petro-chemical based brew of toxic chemicals. This is no ‘leap forward in foam technology’.

It is true that the energy needed to produce soy-based foam is, according to Cargill, who manufactures the soy polyol,  less that that needed to produce the polyurethane foam.  But the way they report the difference is certainly difficult to decipher:  soy based polyols use 23% less energy to produce than petroleum based polyols, according to Cargill’s LCA.   But the formula for the foam uses only 20% soy based  polyols, so by my crude calculations (20% of 50%…) the energy savings of 20% soy based foam would require only 4.6%  less energy than that used to make the petroleum based foam.  But hey, that’s still a savings and every little bit helps get us closer to a self sustaining economy and is friendlier to the planet.

But the real problem with advertising soy based foam as a new, miracle green product is that the foam, whether soy based or not, remains a “greenhouse gas spewing pretroleum product and a witches brew of carcinogenic and neurotoxic chemicals”, according to Len Laycock.

My concern with the use of soy is not its carbon footprint but rather the introduction of a whole new universe of concerns such as pesticide use, genetically modifed crops, appropriation of food stocks and deforestation.  Most soy crops are now GMO:  according to the USDA, over 91% of all soy crops in the US are now GMO; in 2007, 58.6% of all soybeans worldwide were GMO.  If you don’t think that’s a big deal, please read our posts on these issues (9.23.09 and 9.29.09).  The debate still rages today.  Greenpeace did an expose (“Eating Up The Amazon”) on what they consider to be a driving force behind Amazon rainforest destruction – Cargill’s race to establish soy plantations in Brazil.  You can read the Greenpeace report here, and Cargill’s rejoinder here.

In “Killing You Softly“, another sinister side of  soy based foam marketing is brought to light:

“Pretending to offer a ‘soy based’ foam allows these corporations to cloak themselves in a green blanket and masquerade as environmentally responsible corporations when in practice they are not. By highlighting small petroleum savings, they conveniently distract the public from the fact that this product’s manufacture and use continues to threaten human health and poses serious disposal problems. Aside from replacing a small portion of petroleum polyols, the production of polyurethane based foams with soy added continues to rely heavily on ‘the workhorse of the polyurethane foam industry’, cancer causing toluene diisocyanate (TDI). So it remains ‘business as usual ‘ for polyurethane manufacturers.”

Despite what polyurethane foam and furniture companies imply , soy foam is not biodegradable either. Buried in the footnotes on their website, Cargill quietly acknowledges that, “foams made with BiOH polyols are not more biodegradable than traditional petroleum-based cushioning”. Those ever so carefully phrased words are an admission that all polyurethane foams, with or without soy added, simply cannot biodegrade. And so they will languish in our garbage dumps, leach into our water, and find their way into the soft tissue of young children, contaminating and compromising life long after their intended use.

The current marketing of polyurethane foam and furniture made with ‘soy foam’ is merely a page out the tobacco industry’s current ‘greenwashing’ play book. Like a subliminal message, the polyurethane foam and furniture industries are using the soothing words and images of the environmental movement to distract people from the known negative health and environmental impacts of polyurethane foam manufacture, use and disposal.

Cigarettes that are organic (pesticide-free), completely biodegradable, and manufactured using renewable tobacco, still cause cancer and countless deaths. Polyurethane foam made with small amounts of soy derived materials still exposes human beings to toxic, carcinogenic materials, still relies on oil production, and still poisons life.

So what’s a poor consumer to do?  We think there is a viable, albeit expensive, product choice: natural latex (rubber). 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 [3]),  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.

Natural latex is breathable, biodegradeable,  healthier (i.e., totally nontoxic, and mold & mildew proof) and lasts longer than polyfoam – some reports say up to 20 times longer.

Is there really a question as to which to buy?


[1] DFE 2008 Office Chair Foam;  http://en.wikiversity.org/wiki/DFE2008_Office_Chair_Foam#Basics

[2] http://www.foamforyou.com/Foam_Specs.htm

[3] Op cit., http://en.wikiversity.org/wiki/DFE2008_Office_Chair_Foam#Basics





I know the polyester fabric costs less, but what else comes with it?

19 06 2013

When plastic was introduced in 1869, it was advertised as being able to replace natural products like ivory and tortoiseshell in items such as jewelry, combs and buttons – so it would “no longer be necessary to ransack the earth in pursuit of substances which are constantly growing scarcer.”(1)

What a success: Plastics are versatile – they can be hard or soft, flexible or brittle, and are durable, lightweight, formable – in fact, they’re so versatile that they’ve become a vital manufacturing ingredient for nearly every existing industry. They are practically ubiquitous. And now we’re beginning to find that our relationship with plastic is not healthy. Using dwindling fossil fuels to manufacture the stuff, plastic leaches toxic chemicals into our groundwater, litters landscapes and destroys marine life. As Susan Freinkel points out in her book, Plastic: A Toxic Love Story, it’s worth noting that discoveries of plastic’s toxic effects are being made in a world that is at least ten times more plastic than it was half a century ago. In the ’60s, an American might have used about 30 pounds of plastic a year – in 2011, 300 pounds. And we’re producing 300 million tons more every year.(2)

Plastics were marketed as “the material of the future”. And how true that is, because large polymers take practically forever to break down, so much of the plastic that has ever been manufactured is still with us, in landfills, in the plastic filled gyres found in our oceans (where the mass of plastic exceeds that of plankton sixfold) (3), and the stomachs of northern seabirds. And it will stay there for hundreds if not thousands of years.

Just as some chemicals can impact children’s bodies much more than adult bodies, Judith Shulevitz, writing in the New Republic, reminds us: “plastic totally dominates the world of the child. Children drink formula in baby bottles and water in sippy cups, eat food with plastic spoons on bright melamine trays, chew on bath books and rubber ducks, and, if they don’t do these things at your house, they’ll do them at someone else’s or at school, no matter how many notes you write or mad-housewife-ish you’re willing to appear.” (4)

There are many studies to support the belief that these plastics are changing us – but what has really changed is that the scientific understanding of how these chemicals are poisoning us has undergone a conceptual revolution – our grandchildren may see our current attitudes about living with these chemicals as being analogous to doctors in the 1950s who appeared in ads for cigarettes.

Old toxicological notions are being stood on their heads. Certainly, the old “dose makes the poison” notion, which was first expressed by Paracelsus in the 16th century and which means that a substance can only be toxic if it is present in a high enough concentration in the body – because all things are poisonous in the right amounts. He wrote: “All substances are poisons; there is none which is not a poison. The right dose differentiates a poison from a remedy”. But today scientists are finding that timing of exposure might be the critical factor – a fetus might respond to a chemical at one-hundredfold less concentration or more than in an adult, and when the chemical is taken away the body is altered for life. Another theory is known as the “developmental origins of health and disease,” or DOHaD (for more about DOHaD, click here), and it paints a picture of almost unimaginably impressionable bodies, responsive to biologically active chemicals until the third generation.(5)

New methods have been developed which have taken the guesswork out of what were once theories: for example, biomonitoring now means that scientists can actually discover the degree to which people have been exposed to poisonous stuff when in the past their conclusions were largely guesswork; and microarray profiling, which means we’re beginning to understand how tiny doses of certain chemicals switch genes on or off in harmful ways during exquisitely sensitive periods of development.

Exposure to all that plastic has a cumulative effect. Now toxicologists can see that lots of tiny doses from many different estrogen-mimicking chemicals entering the body by multiple pathways can have a big impact. “If you’re being exposed to two-hundred fifty chemicals and only thirty of them have estrogenic activity, but they’re each very low, still, thirty of them might add up to be significant,” says Jerrold Heindel, of the National Institute of Environmental Health Sciences (NIEHS).

Judith Shulavith asks– if we live in this plastic environment – why we’re not sicker than we are? And sicker than we used to be? “The answer is, we’re healthier in some ways and sicker in others. Medical advances mean we’re likelier than ever to survive our illnesses, but all kinds of diseases are on the rise. Childhood cancers are up 20 percent since 1975. Rates of kidney, thyroid, liver, and testicular cancers in adults have been steadily increasing. A woman’s risk of getting breast cancer has gone from one in ten in 1973 to one in eight today. Asthma rates doubled between 1980 and 1995, and have stayed level since. Autism-spectrum disorders have arguably increased tenfold over the past 15 years. According to one large study of men in Boston, testosterone levels are down to a degree that can’t be accounted for by factors such as age, smoking, and obesity. Obesity, of course, has been elevated to the status of an epidemic.”(6)

There are many ways to explain upticks in rates of any particular ailment; for starters, a better-informed populace and better tools for detecting disease mean more diagnoses. Other environmental stressors include Americans’ weirdly terrible eating habits, our sedentary lifestyle, and stress itself. But why can’t we just figure this out and come to some conclusions about certain chemicals as the cause of certain diseases? John Vandenberg, a biologist, explains the difficulty : “Well, one of the problems is that we would have to take half of the kids in the kindergarten and give them BPA and the other half not. Or expose half of the pregnant women to BPA in the doctor’s office and the other half not. And then we have to wait thirty to fifty years to see what effects this has on their development, and whether they get more prostate cancer or breast cancer. You have to wait at least until puberty to see if there is an effect on sexual maturation. Ethically, you are not going to go and feed people something if you think it harmful, and, second, you have this incredible time span to deal with.”(7)

Which diseases, exactly, have fetal origins and which chemicals have the power to sidetrack development, and how, is the goal of a giant, 21-year study of 100,000 children called the National Children’s Study (NCS), under the auspices of the National Institutes of Health. However, in 2013, it was announced that the decade-old effort would undergo radical restructuring to cut costs.(8)

Meanwhile, what can you do to protect yourself and your family, since the government isn’t doing that job?  I’ll have some ideas next week.

(1) Freinkel, Susan, “Plastic: Too Good to Throw Away”, The New York Times, March 17, 2011
(2) Ibid.
(3) Moore, C.J., et al, “Density of Plastic Particles found in zooplankton trawls from coastal waters of Northern California to the North Pacific Central Gyre”, Algalita Marine Research Foundation
(4) Shulevitz, Judith, “The Toxicity Panic”, The New Republic, April 7, 2011
(5) Ibid.
(6) Ibid.
(7) Groopman, Jerome, “The Plastic Panic”, The New Yorker, May 31, 2010.
(8) Belli, Brita, “Changes to Children’s Study Threaten its value, experts say”, Simons Foundation Autism Research Initiative; 7 March 2013





Chrome-free leather?

6 03 2013

leather sofaLast week we took a look at chromium in textiles – and leather. With the increased interest in avoidance of certain chemicals and industrial products that are particularly harmful to our environment, it’s not surprising that manufacturers are becoming ingenious in pointing out attributes that play to this script. So we now see claims for “chrome free” leather as being “eco friendly”.

Although most leather is tanned using chromium (from 80 – 95% of all leather produced uses chrome tanning [1]) there is a third type of leather tanning, called aldehyde tanning, which like vegetable tanning does not use chromium.

Often leather is advertised as being “pure aniline”, “full or semi aniline”, “top grain” “nubuk”- these are just terms which describe how the dye is applied or in the case of “top grain”, where the hide comes from on the animal. These terms have nothing to do with tanning.

Let’s look at leather tanning for a minute and find out what that means:

Sometimes leather manufacturers will tell you that they don’t use the toxic form of chromium in tanning – the toxic form is called chromium VI or hexavalent chromium. And that is correct: chromium tanned leathers use chromium III salts (also called trivalent chromium) in the form of chromium sulfate. This form of chromium is found naturally in the environment and is a necessary nutrient for the human body. However, the leather manufacturers fail to explain that chromium III oxidizes into chromium VI in the presence of oxygen combined with other factors, such as extremes in pH. This happens during the tanning process. Chromium-tanned leather can contain between 4 and 5% of chromium [2] – often hexavalent chromium, which produces allergic reactions and easily moves across membranes such as skin. End of life issues, recovery and reuse are a great concern – chromium (whether III or VI) is persistent (it cannot be destroyed) and will always be in the environment. Incineration, composting and gasification will not eliminate chromium.

Vegetable tanning is simply the replacement of the chromium for bark or plant tannins –all other steps remain the same. And since there are about 250 chemicals used in tanning, the replacement of chromium for plant tannins, without addressing the other chemicals used, is a drop in the bucket. Last week I mentioned some of the other 249 chemicals routinely used in tanning: alcohol, coal tar , sodium sulfate, sulfuric acid, chlorinated phenols (e.g. 3,5-dichlorophenol), azo dyes, cadmium, cobalt, copper, antimony, cyanide, barium, lead, selenium, mercury, zinc, polychlorinated biphenyels (PCBs), nickel, formaldehyde and pesticide residues.[3]

Aldehyde tanning is the main type of leather referred to as “chrome-free”, and is often used in automobiles and baby’s shoes. Aldehyde tanning is often referred to as “wet white” due to the pale cream color it imparts to the skins. But aldehydes are a group of chemicals that contain one chemical which many people are familiar with: formaldehyde. And we all know about formaldehyde: it is highly toxic to all animals; ingestion of as little as little as 30 mL (1 oz.) of a solution containing 37% formaldehyde has been reported to cause death in an adult human[4] and the Department of Health and Human Services has said it may reasonably be anticipated to be a carcinogen.

Aldehyde tanning essentially uses formaldehyde, which reacts with proteins in the leather to prevent putrefication. BLC Leather Technology Center, a leading independent leather testing center, states that leathers should contain no more than 200ppm of formaldehyde for articles in general use. If the item is in direct skin contact this should be 75ppm, and 20ppm for items used by babies (<36 months). Typically, with modern tanning techniques, leathers contain 400ppm or less.[5] Yet that far exceeds levels set elsewhere – in New Zealand, for example, acceptable levels of formaldehyde in products is set at 100 ppm[6] – the European Union Ecolabel restricts formaldehyde to 20 ppm for infant articles, 30 ppm for children and adults, while GOTS prohibits any detectable level.

BLC Leather Technology Center commissioned a study by Ecobilan S.A. (Reference BLC Report 002) to do a life cycle analysis to evaluate the various tanning chemicals, to see if there was an environmentally preferable choice between chrome, vegetable and aldehyde based processes. The result? They found no significant differences between the three – all have environmental impacts, just different ones. These LCA’s demonstrate that tanning is just one of the impacts – other steps may have equal impacts. Chrome was cited as having the disadvantage of being environmentally persistent. “Another consideration, in terms of end-of-life leather or management of chrome tanned leather waste, is the possibility of the valency state changing from the benign Cr III to the carcinogenic Cr VI.”[7]

So much for “chrome free” leather. But since all three tanning processes impact the environment to the same degree, the least toxic (vegetable) is the one I’d choose. But there are precious few tanneries doing vegetable tanned leather.

One issue which is a hot topic in leather production is that of deforestation and the sourcing of skins from Brazil – cattle ranching in Brazil accounted for 14% of global deforestation and ranches occupy approximately 80% of all deforested land in the Amazon. [8] Greenpeace and the National Wildlife Federation (NWF) aims to stop all deforestation in the Amazon by encouraging the meat processors to insist that their suppliers register their farms and map and log their boundaries as a minimum requirement. They also encourage companies to cancel orders with suppliers that are not prepared to stop deforestation and adhere to these minimum requirements. Many of the Leather Working Group (LWG)(for a list of these members, see footnote 9) member brands have made commitments to a moratorium on hides sourced from farms involved in deforestation and LWG itself has a project to identify and engage with the key stakeholders in Brazil, investigate traceability solutions, conduct trials and implement third party auditing solutions.
________________________________________
[1] Richards, Matt, et al, “Leather for Life”, Future Fashion White Papers, Earth Pledge Foundation
[2] Gustavson, K.H. “The Chemistry of Tanning Processes” Academic Press Inc., New York, 1956.
[3] Barton, Cat, “Workers pay high price at Bangladesh tanneries”, AFP, Feb. 2011
[4] Agency for Toxic Substances & Disease Registry, “Medical management guidelines for formaldehyde”, http://www.atsdr.cdc.gov/mmg/mmg.asp?id=216&tid=39
[5] BLC Leather Technology Center Ltd, “Technology Restricted substances – Formaldehyde”, Leather International, November 2008, http://www.leathermag.com/news/fullstory.php/aid/13528/Technology_Restricted_substances-Formaldehyde.html
[6] “Evaluation of alleged unacceptable formaldehyde levels in Clothing”, Wellington, New Zealand: New Zealand Ministry of Consumer Affairs, October 17, 2007.
[7] http://www.leathermag.com/news/fullstory.php/aid/13479/Technology_Restricted_substances-Chrome_VI_story.html
[8] “Broken Promises: how the cattle industry in the Amazon is still connected to deforestation…” Greenpeace, October 2011; http://www.leatherworkinggroup.com/images/documents/Broken%20promises%20-%20Oct11FINAL.pdf
(9) Currently the consumer brands involved with the LWG are: Adidas-group, Clarks International, Ikea of Sweden, New Balance Athletic Shoe, Nike Inc, Pentland Group including (Berghaus, Boxfresh, Brasher, Ellesse, Franco Sarto, Gio-Goi, Hunter, KangaROOS, Mitre, Kickers (UK), Lacoste Chaussures, ONETrueSaxon, Radcliffe, Red or Dead, Speedo, Ted Baker Footwear), The North Face, The Timberland Company, Wolverine World Wide Inc including (CAT, Merrel, Hush Puppies, Patagonia, Wolverine, Track n Trail, Sebago, Chaco, Hytest, Bates, Cushe, Soft Style). New brands recently joined are Airwair International Ltd, K-Swiss International, Marks & Spencers and Nine West Group.





Antimony in fabrics

6 02 2013

antimonySynthetic fibers are the most popular fibers in the world – 65% of the world’s production of fibers are synthetic, and 35% are natural fibers. (1) Fully 70% of those synthetic fibers are polyester. There are many different types of polyester, but the type most often produced for use in textiles is polyethylene terephthalate, abbreviated PET. Used in a fabric, it’s most often referred to as “polyester” or “poly”. It is very cheap to produce, which is the primary driver for its use in the textile industry.

The majority of the world’s PET production – about 60% – is used to make fibers for textiles; and about 30% is used to make bottles. Think about that for a moment – bet you didn’t realize that those bottles that we’re all being told to recycle make up just 30% of PET production! Annual PET production requires 104 million barrels of oil – that’s 70 million barrels just to produce the virgin polyester used in fabrics.(2) That means most polyester – 70 million barrels worth – is manufactured specifically to be made into fibers, NOT bottles. Of the 30% of PET which is used to make bottles, only a tiny fraction is recycled into fibers. But the idea of using recycled bottles – “diverting waste from landfills” – and turning it into fibers has caught the public’s imagination. There are many reasons why using recycled polyester (often called rPET) is not a good choice given our climate crisis, but today’s post is concentrating on only one aspect of polyester: the fact that antimony is used as a catalyst to create PET. We will explore what that means.

Antimony is present in 80 – 85% of all virgin PET. Antimony is a carcinogen, and toxic to the heart, lungs, liver and skin. Long term inhalation causes chronic bronchitis and emphysema. The industry will say that although antimony is used as a catalyst in the production process, it is “locked” into the finished polymer, and not a concern to human health. And that’s correct: antimony used in the production of PET fibers becomes chemically bound to the PET polymer so although your PET fabric contains antimony, it isn’t available to your living system. (3)

So what’s the concern? Antimony is leached from the fibers during the high temperature dyeing process. The antimony that leaches from the fibers is expelled with the wastewater into our rivers (unless the fabric is woven at a mill which treats its wastewater). In fact, as much as 175ppm of antimony can be leached from the fiber during the dyeing process. This seemingly insignificant amount translates into a burden on water treatment facilities when multiplied by 19 million lbs each year – and it’s still a hazardous waste when precipitated out during treatment. Countries that can afford technologies that precipitate the metals out of the solution are left with a hazardous sludge that must then be disposed of in a properly managed landfill or incinerator operations. Countries who cannot or who are unwilling to employ these end-of-pipe treatments release antimony along with a host of other dangerous substances to open waters.

But what about the antimony that remains in the PET fabric? We do know that antimony leaches from PET bottles into the water or soda inside the bottles. The US Agency for Toxic Substances and Disease Registry says that the antimony in fabric is very tightly bound and does not expose people to antimony, (4) as I mentioned earlier. So if you want to take the government’s word for it, antimony in PET is not a problem for human health – at least directly in terms of exposure from fabrics which contain antimony. (Toxics crusader William McDonough has been on antimony’s case for years, however, and takes a much less sanguine view of antimony. (5) )

Antimony is just not a nice thing to be eating or drinking, and wearing it probably won’t hurt you, but during the production process it’s released into our environment. Recycling PET is a high temperature process, which creates wastewater tainted with antimony trioxide – and the dyeing process for recycled PET is problematic as I mentioned in an earlier post. Another problem occurs when the PET (recycled or virgin) is finally incinerated at the landfill – because then the antimony is released as a gas (antimony trioxide). Antimony trioxide has been classified as a carcinogen in the state of California since 1990, by various agencies in the U.S. (such as OSHA, ACGIH and IARC) and in the European Union. And the sludge produced during PET production (40 million pounds in the U.S. alone) when incinerated creates 800,000 lbs of fly ash which contains antimony, arsenic and other metals used during production.(5)

So the continued use of polyester exposes our environment (and remember, the “environment” means you and me) to more antimony, which is a heavy metal and not good for us. So if we care about leaving a liveable planet for our children, we should pay attention to the types of fibers we’re supporting.

(1) “New Approach of Synthetic Fibers Industry”, Textile Exchange, http://www.teonline.com/articles/2009/01/new-approach-of-synthetic-fibe.html
(2) Polyester, Absolute Astronomy.com: http://www.absoluteastronomy.com/topics/Polyester and Pacific Institute, Energy Implications of Bottled Water, Gleick and Cooley, Feb 2009, http://www.pacinst.org/reports/bottled_water/index.htm)
(3) Shotyk, William, et al, “Contamination of Canadian and European Bottled waters with antimony from PET containers”, Journal of Environmental Monitoring, 2006. http://www.rsc.org/delivery/_ArticleLinking/DisplayHTMLArticleforfree.cfm?JournalCode=EM&Year=2006&ManuscriptID=b517844b&Iss=2
(4) http://www.atsdr.cdc.gov/toxprofiles/phs23.html
(5) http://www.victor-innovatex.com/doc/sustainability.pdf