The Signal: News and Notes from the Pharos Team

From The Smokestack To Your Floor – Post Consumer Fly Ash?

Tom Lent October 24th, 2012 7 comments

*** Nov. 20, 2012 update:  NSF International Retracts Post-Consumer Fly Ash Designation. Click here to read. ***

Should fly ash from coal fired power plants be considered post-consumer recycled material?  Amazingly, NSF International, the certification and standards institution, thinks so.  Two recent decisions added fuel to the debate about the use of coal-fired power plant waste in building materials:  First, NSF designated “Celceram” -- coal fly ash marketed by Boral Material Technologies -- as a 100% post-consumer product.  Then, by a 14-4 vote, an NSF Standards Committee decided to eliminate language from the carpet sustainability standard, NSF-140, that defines fly ash as pre-consumer content only. [1]

Widely used in carpet backing, fly ash products such as Boral’s Celceram are the byproduct of burning coal. EPA is investigating concerns about coal ash. A 2010 EPA study of Metals in Air Pollution Control Residues from Coal-Fired Power Plants subjected fly ash and FGD (flue gas desulferization) residue samples from 34 different coal fired power plants to multi point leachate tests. The study found that significant numbers of samples exceeded a variety of regulatory toxicity thresholds for heavy metals such as arsenic, barium, chromium and selenium and concluded that the standard single point tests frequently used in the industry are of lmited value.

After years of vigorous promotion of the “beneficial use” of fly ash as a recycled material, EPA has more recently struggled with how best to regulate this hazardous waste material, caught between fly ash’s massive disposal problems and continuing concerns about lifecycle problems from dispersing the toxic heavy metals in building products.

Fly ash has long been considered a pre-consumer (post-industrial) recycled material. The NSF decision to accept Boral’s post-consumer claim is a high stakes one, doubling the value of the recycled content in the LEED rating system [2] and opening the door to higher ratings in NSF 140 [3]. Fly ash companies apparently unsuccessfully approached several certifier organizations with the claim before finding NSF willing.

Representatives of several other certifying bodies I interviewed for this story were unanimous in condemning the NSF decision, noting that fly ash is a byproduct of an industrial process and should not count as a post-consumer product any more than the shavings from a milling operation would be considered post-consumer.  

Wes Sullens, Program Manager in the Green Building group of StopWaste.Org, calls the application of the term ‘post-consumer’ to fly ash “incongruous,” noting that a post-consumer claim is intended to be used where products go to market, are used directly by consumers, and then collected for recycling. Everyone I interviewed for this story felt that the ISO standard (ISO 14021) is pretty clear that material diverted from the waste stream during a manufacturing process is pre-consumer material.

A representative of a major carpet company, although currently using fly ash in their backings, worries that this designation will actually create a disincentive to use higher-value recycled content streams – namely the old carpet that the industry has struggled to reclaim. The manufacturer, for now, has decided not to adopt the post-consumer designation in their product specs despite the gain they could realize in LEED credits.

We strongly agree and encourage other manufacturers to follow suit and leave fly ash designated as pre-consumer recycled content. We think this fly ash post-consumer designation damages the credibility of recycled content claims and the NSF 140 program. These decisions open the door to all sorts of power plant wastes, from solid waste incinerator ash to spent fuel rods. By the NSF’s logic, any of these wastes could be defined as “post-consumer” material.

We also encourage the USGBC to reject this claim and use this opportunity to clarify the definition of post-consumer recycled content. Meanwhile, specifiers will need to scrutinize post-consumer recycled content claims more carefully to avoid this kind of greenwash, even if third party certified.

The fly ash post-consumer debate comes at an interesting time just as the USGBC has released the latest public comment version of LEED V4 with significant new material credits that address toxic content and that highlight responsible sourcing of raw materials. The sourcing credits start to put the kind of spotlight on the impacts of agricultural and mining practices that the FSC credit has long put on forestry practices. Maybe it is also time to take a close look at the sustainability of recycling practices and adjust certifications and rating systems to incent those products that facilitate true closed loop recycling and avoid the production and recirculation of toxic materials.  

(revised 12/11/12 to reference and explain an EPA study)


[1] The committee struck this sentence:  “Coal fly ash used as a filler or binding agent qualifies as post-industrial/pre-consumer content only, as do other post-industrial/pre-consumer fillers and binders” replacing it with:  “The determination of post-industrial/pre-consumer or post-consumer content shall comply with an existing recognized national or international standard definition.”

[2] Pre-consumer recycled content is worth only 50% of the value of post-consumer content in LEED Material credits.

[3] This opens the door for any carpet manufacturer to use fly ash to achieve the NSF-140 standard Platinum rating.


Tom L, December 11th, 2012

In response to the comment from Fred and a request from Boral we have clarified the phrase "... routinely exceeds toxicity tests..." to reference and more specifically draw from the multi point EPA study from which the information originates. Subjecting 73 fly ash and FGD (flue gas desulferization) residue samples from 34 different coal fired power plants to leachate tests under varying Ph regimens, the EPA found significant excursions above a variety of important regulatory levels in  samples. They further concluded that "the use of total content, single-point leaching tests and linear partitioning (approaches frequently used in fate and transport modeling to represent the source term) are unable to predict leaching behavior over the wide range of potential use and disposal scenarios with diverse chemical and hydraulic conditions." The full text of the study is available without subscription at the link above.

Fred, November 20th, 2012

"... routinely exceeds toxicity tests..." Good example of purely emotional statement.  Meaningless, aside from the inference that we should be afraid.  No context.  No definition.  You would do yourself and your readers a great service and raise your credibility by telling the truth throughout your blog.

Jim V, November 20th, 2012

Thanks Greta and NSF International for your openness and retraction. I wrote about it in this new blog, posted here:

Greta Houlahan, November 19th, 2012

NSF International, an independent organization that writes standards, and tests and certifies products for the building, food, water and consumer goods industries, has retracted verification of the claim that Boral Material Technologies fly ash is a post-consumer material. Even though there is room for interpretation when classifying specific recycled materials against current definitions of "post-consumer," historically fly ash has been classified as a pre-consumer waste, and NSF agrees this is the generally accepted classification. Additionally, NSF Sustainability intends to pursue, through the ISO technical committee, a clarification in language describing post-consumer recycled content in the ISO 14021 environmental labels and declarations standard. 

Greta Houlahan, October 31st, 2012

We appreciate the recent interest in NSF Standard 140, the American National Standard for sustainability assessment for carpet. As has been acknowledged in the recent posting, the Joint Committee responsible for the content of the Standard has considered changes regarding coal fly ash. With respect to NSF certifications to this Standard, NSF has not recognized coal fly ash as post-consumer in any NSF Standard 140 certifications and will not unless the Joint Committee agrees to make a change, and that change is adopted and published. For those interested in tracking the process, which is fully open and transparent, visit

GreenRenovation, October 26th, 2012

While I'm no shill for industry, I do think we need to bring a bit less emotion to the discussion of materials and their use.  How something is classified should certainly stay true to the intent of a standard such as post-consumer v. post-industrial.  Nonetheless, opponents of coal paint with an unnaturally large brush to color any product that recycles a coal by- or waste-product as hazardous.  And this is obviously an attempt to attack coal itself using building products as their foil. The determination of hazard should derive not only from the content of the product, but also from the ability of the hazardous component in a given product to migrate out of that product and impact the public.  If carpeting itself, for example, is made from hazardous materials and those hazardous materials leach out when a baby crawls accross the floor, then a problem clearly exists.  If, however, the carpet backing contains a hazardous substance, that that substance never comes into end-user contact, the risk is lower or even non-existent. Certainly there is still a risk of release upon disposal.  But hopefully, as the article notes, there are vigorous recycling programs for the waste carpet pads, and if there are not, there should be.   Utlimately these issues are important and should be discussed.  But perhaps we can debate them with a bit less emotion and bit more data and actual risks of specific materials in particular uses.

Steve, October 25th, 2012

Good call!

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