C6, C8 and See No Evil

Site: Gary S. Selwyn, PhD – Sustainable, biopolymer finishing and dyeing of textiles and footwear

New Year’s Day 2016 brought us more than a stock market correction and a blizzard: it also brought an end to harmful fluorocarbons used in industrial products everywhere.  So at least we have something to celebrate – right?  Well, not exactly.

As Michelangelo once said, “The greater danger for most of us lies not in setting our aim too high and falling short; but in setting our aim too low, and achieving our mark.” So it is with the EPA’s ban on certain fluorocarbons starting in 2016. Here, the main culprit is perfluorooctanic acid, also known as PFOA, a fluorochemical widely used in the production of nonstick cookware, stain resistant carpet, microwave popcorn bags and apparel for athletic and outdoor wear.  PFOA and other long-chain perfluorinated compounds (PFCs) help make apparel, upholstery and carpet repellent to water and oils, as well as being stain resistant.

The EPA to the Rescue…

After a lengthy legal battle that involved the EPA, certain chemical manufacturers, chemical industry employees and local residents poisoned by PFCs, PFOA is now clearly identified and banned as a toxin and a carcinogen. Yet, it is found in the bloodstream of 98% of Americans.  PFOA is found in our drinking water, our homes and in our clothes.  Even though only trace levels of PFOA are found in most apparel and carpet, those levels are now deemed to be too high: PFCs must be contained to mitigate the public risk, the EPA concluded. To read the whole sad, story, click here.

Having identified this toxic and dangerous chemical in our environment, the EPA did what it does best: ban that chemical – but then continue to allow all the other similar toxins and suspected carcinogens to continue to flood the apparel that contacts our skin, our drinking water, our backyards and our homes. So, as of January 1, 2016, long chain, fluorochemicals having at least 8 perfluorinated carbon atoms (these are known as “C8”) cannot be imported or manufactured in the US without a special exemption by the EPA.  Of course, that does not mean that OEMs cannot first use up the C8 PFCs they stockpiled before Jan 1… and there is no requirement for manufacturers to label their C8-containing products manufactured after Jan 1.

Many conscientious manufacturers have already switched to the “safer” PFCs that have only 6 or less perfluorinated carbon atoms, also called “C6”.  These are allowed because they are believed to degrade faster than the C8 PFCs and because do not appear to accumulate as much in the human body.  Because C6 is not banned at this time, you will find this toxin in your sports apparel, hiking jackets and carpet.  However, many knowledgeable people recognize that C6 PFCs are suspected carcinogens. In fact, C6 PFC has a sizeable “impurity” of the banned C8 PFC.  Some unscrupulous chemical suppliers intentionally keep a high impurity level of C8 in their C6 – to make it work better!

This is starting to sound like the “good” white asbestos and the “bad” blue asbestos of years ago. Both forms of asbestos were known to be carcinogenic, but blue asbestos was banned about 15 years before white asbestos was banned. During that time, countless people were exposed to this carcinogen and homes and businesses were built using white asbestos that later needed to be removed – at great cost. The delay was “needed” because there was “no substitute” – until there was a substitute. Do we use asbestos today?  Is it missed?  Same with PFCs.  The substitute for PFCs already exists – despite the vocal denials of major apparel brands.

A valid question for C6 PFCs is, “are these safe”?  But the wiser question is whether we need PFCs at all?

Is C6 Safe?

The reason that PFCs are used is for water and oil repellency (hydrophobicity and oleophobicity). This repellency comes from the nonpolar nature of PFCs (for hydrophobicity) and the London dispersion forces that typify a carbon atom that is fully bonded to fluorine atoms (for oleophobicity).  So, oleophobicity can only be obtained from a PFC compound.

Hydrocarbons are not oleophobic.  However, hydrocarbons can be extremely hydrophobic, which is the greater need.  No matter how much you mix water and gasoline, these two liquids will forever repel each other. Hydrophobicity comes from non-polar compounds, which is Nature’s approach for water repellency in the plant and animal kingdoms. Plus, these hydrophobic chemicals biodegrade and so are sustainable: 200,000 years of evolution have served us well.

Nature does not make PFCs (how wise is Nature???), so living organisms have not adapted over the ages to deal with PFCs. While C6 PFCs may have a shorter half-life in the human body than C8 PFCs – is that OK?  How much reduction in lifespan are we willing to trade for a pair of pants that are resistant to salad dressing?

The longer the carbon chain that is either nonpolar or perfluorinated (i.e., fully bonded to fluorine atoms) the better the repellency performance.  So, there is no surprise when C6 PFCs do not perform as well as C8 – or C10 or C12 for that matter. Because the performance of C6 PFCs is not as good as C8 PFCs, more C6 PFC is needed to achieve comparable performance. That means that your new $400 outdoor jacket needs a higher level of C6 than it previously required when a C8 PFC was used.  Is this the trend we want to encourage – knowing that C6 is still bio-persistant and a suspected carcinogen? Does it make sense to use more of a compound because it may be less toxic and carcinogenic?

How this relates to clothing

Next, consider the case of one major apparel brand that adopted a C6 compound to replace the C8 PFC it previously used for a durable, water-repellent treatment (DWR).  In this case, perfluorohexanoic acid was used.  This C6 PFC is not banned by the EPA, though there are few chemical manufacturers making it in the US.  The reason is that it is nearly identical to the notorious PFOA compound (less only 2 carbons) that is fully banned and which started the EPA action. Perhaps perfluorohexanoic acid is hard to obtain in the US because of its potential liability? Want that on your apparel?

However, it is still available from China and may be legally imported.  Chinese chemical vendors are not known for high purity, so even if it is 99.9% pure (an unlikely event), it is still likely to have 1000 ppm of actual PFOA impurity, which is about 100,000 times more PFOA in the C6 apparel than was in the previously banned product. Is this safer? Would you want this C6 treated apparel against your skin, especially given that transdermal transport of PFOA into the body has been demonstrated in NIH studies.  If the transition to C6 PFC means that the toxin in our clothing is 1 million times higher today than the recommended maximum, It would appear that banning C8 PFCs has not been a success. It is a case of aiming too low and meeting that mark. That does not mean C8 PFCs should be allowed – it says all PFCs should be banned.

Curiously, the Safety Data Sheet (formerly MSDS) for perfluorohexanoic acid says that any clothing “contaminated” by this C6 PFC should be “responsibly disposed”.  What does that say about intentionally loading performance clothing with this toxin simply to have an oleophobic finish?

Do we need PFCs?

This issue has been publicly challenged by Greenpeace and others. Every time we wash apparel that is PFC-treated for a DWR treatment, PFCs are removed by the laundry and goes down the drain. Most C6 DWR treatment does not even last past 15 washes, so your jacket’s performance is steadily eroded.  PFCs are not filtered out by municipal waste treatment plants, which are why we find PFCs in our lakes, rivers and oceans, and also in our blood.

Chemical manufacturers would like you to believe that PFCs are needed for a DWR treatment, but that is simply not so. Many apparel brands have said the same. PFCs cost more than comparable hydrocarbons, so there is a profit motive for that.  While it is true that the London dispersive forces of PFCs provide a degree of oleophobicity, this is a very weak force field. The oil repellency protection provided by PFCs is weak at best and can be compared to wearing a seat belt that works only in certain crashes and only at under 10 mph.  For example, the effective oleophobicity of a PFC-based DWR treatment will keep a gently placed droplet of certain oils from penetrating the fabric for up to a minute or so. But, vegetable oil, gasoline, and other light oils will immediately soak in. All oils will penetrate a DWR if a drop falls from sufficient distance (certainly the distance from head to lap!) or is pushed in, such as by sitting on it.

Once in the fabric, oil stains are harder to remove from a DWR-treated fabric because soap and detergent are similarly repelled by PFCs.  This staining is so persistent that apparel brands must add “stain release” agents to help remove grease stains for home laundry cleaning.  The stain release agent is…. Yes –yet another fluorocarbon that is removed by laundry, hopefully with some of the stain.  That lasts for just a few washes, but adds to the contamination of our drinking water. The stain is eventually removed when the DWR finish is also removed.

The PFC-free, Alternative Approach

Additionally, PFCs do not do as well for hydrophobicity as a hydrocarbon-based DWR treatment. Better water repellency can be obtained from Nature’s hydrocarbons. Rain repellency is what most consumers want in outdoor and athletic apparel.  This comes from a non-polar, polymeric DWR treatment and the longer the carbon chain length, the better the water repellency.  Green Theme Technologies (GTT) uses a hydrocarbon-based, DWR treatment that comes from longer length C18-C30 compounds – without fluorine.  This far outperforms both C6 and C8 PFCs for water repellency, in addition to being non-toxic and biodegradable.  Even better, it has been shown to last for 100 wash/dry cycles, so it is not polluting municipal water treatment facilities and means that an outdoor jacket lasts far longer for its intended purpose. That treatment is not only free of all PFCs – it also does not use or consume any water.

But, what about the oil repellency?  Fortunately, it doesn’t rain hexane, but accidents do happen.  Stain removal is what laundry is used for.  Since the hydrocarbon DWR treatment does not wash out, it can be laundered as frequently as needed without removing the treatment.  The hydrocarbon-based polymer does not block the stain-removing power of laundry detergent, meaning that an oil-based stain can be removed by washing – not like the PFC treatment it replaces. It does not contaminate groundwater and does not cause cancer.  Maybe there is a reason that Nature does not use PFCs?  Shouldn’t that be used for water-repellent apparel?

Speak no evil?

Greenpeace has strongly criticized major outdoor apparel brands for using these toxins in outdoor clothing.  Recently, Greenpeace found C8 PFCs in apparel that was supposed to be free of these banned PFCs.  I side with Greenpeace.  They see the evil that everyone else tries to not see and not hear. We don’t need PFCs in our wetlands or in our blood.  But, we do like to stay dry in the rain, as we enjoy the great outdoors. And if I do drop some salad dressing on my pants, then dropping the pants into the laundry solves that problem – without creating a world of other problems.

What is really needed is chemical labeling on our apparel as it is impossible for a consumer to know whether they are wearing a carcinogen or not. With that knowledge, most would wisely chose a hydrocarbon DWR finish. It is widely recognized that every employee has a right to know the chemicals present in their workplace, but when it comes to our clothes and consumers, we are treated like the three monkeys: hear no evil, see no evil, and say no evil – until Greenpeace speaks the truth everyone cannot help but listen. Keep it up, Greenpeace! Fewer toxins that we are exposed means a better life for everyone!