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[GreenYes] CARB Fly Ash Comments Needed by 10/24 -Please send them a note.

PLEASE send a letter of strong opposition to the California Air Resources Board (CARB) to oppose their recommended proposal to add to their list of early action measures to reduce greenhouse gas (GHG) emissions the measure to add fly ash additions in the production of Portland Cement. 


Click here  to submit your comments or go to 


Tell CARB to remove this measure from their expanded list, 

(see page 100 of the pdf /page B69 of the document)



Ask them to remove ?fly ash additions? from their mitigation measure #B20  [ID NUMBER: EA B-1, B-2,TITLE: CEMENT (B): BLENDED CEMENTS


Tell them to remove ?fly ash additions in cement? from mitigation measure #B20  because:


  1. True greenhouse gas (GHG) emission reductions have not  been scientifically shown to result from ?fly ash additions in cement? for California.--Estimates indicate GHG emissions are in fact HIGHER when back to back comparisons are conducted that include primary C2G emissions including the shipping of fly ash to CA.     
  2. ?Fly ash additions in cement? are not a sustainable measure.  They perpetuate and prolong coal burning activities and dependancies disadvantaging the viability of emerging alternative energy developments. 
  3. Fly ash?s toxic content poses potentially significant health and safety risks to communities, children, workers, and the public at large in its processing, foreseeable uses, and disposal. 


COMMENTS ARE DUE 10/24 or sooner for the 10/25 hearing. 


 Below is further detailed discussion on this important topic: 




Claims that fly ash use reduces greenhouse gas emissions are false. 

For each ton of fly ash generated, 24 tons of C02 are emitted - just from burning the coal. Every 8 to 10 tons of coal burned produces 1 ton of fly ash.  Burning one ton of coal for electricity produces 2.86 tons of CO2, thus just "producing" one ton of fly ash to emits more than 28.6 tons of CO2[1] (see references listed below).  This CO2 "cost" number excludes significant additional emissions inherent in fly ash use including  emissions generated by coal mining, the fugitive coal mine methane emissions, and importantly the emissions from the shipping and transporting of the fly ash - often across the country or even from Canada[2].  Methane is about 21 times more powerful at warming the atmosphere than CO2[3]

There is no definitive report shows that fly ash additions in cement for California would result in reduced greenhouse gas emissions.  Prior to instituting fly ash additions as a measure for AB 32, a comprehensive sound scientific full lifecycle analysis for California application needs to be conducted with peer and stakeholder review to verify whether or not greenhouse gas emissions are reduced.  


Fly Ash use in cement is not a sustainable step.  

As we know in the United States, most carbon dioxide (98 percent) is emitted as a result of the combustion of fossil fuels; consequently, carbon dioxide emissions and energy use are highly correlated. The remaining 2 percent of carbon dioxide emissions comes from a variety of other industrial sources[4].  Using recent U.S. data, coal contributes 82% of electric power sector CO2 emissions, about 35.3% of total national CO2 emissions - Cement production contributes about 0.8% of total national CO2 emissions[5].  According to the American Coal Ash Association, more than 71 million tons of fly ash are produced annually[6].  Fly ash may replace up to 35% of the cement in concrete. Even using industry's emission factors, if fly ash was used in the production of all of the cement in the U.S. the overall potential impact would on national CO2 emissions be less than 0.3%.
Its clear that there is a high priority need to d
evelop sustainable alternative energy sources.   Burning coal to produce one ton of fly ash to displace Portland cement emits more than 27.6 times the CO2 equivalents as using alternative energy and Portland cement, resulting in an annual net increase of CO2 equivalents of more than 358 million tons of carbon dioxide. This estimate does not include significant methane emissions associated with coal mining or transportation.  Using the coal fly ash in cement is a band-aid to and a subsidy to the coal industry.  It avoids the costly disposal fees for the coal industry that they would otherwise need to pay.  Using coal fly ash in cement shifts the disposal and toxicity onus away from the coal burning waste generators driving the price for coal energy down making it difficult for emerging alternative energy choices to compete and be viable in the marketplace.


Coal Fly ash contains toxicity that may pose a significant risk in its foreseeable uses. 

Coal fly ash throughout the US has been well documented to contain toxics.  Coal fly ash has been documented to contain mercury.   It is however an exempted material by Federal law and is not currently labeled or tested for its toxic content.  There are many kinds of coal and many types of coal power plants and a variety of end of pipe control technologies resulting in variations in toxicity based on power plant emissions controls, start up/operations procedures, types of  coal used, and the co-firing of other fuels or even hazardous wastes. Further, as emissions controls on coal fired power plants are improved, fly ash toxins are becoming further concentrated with toxics.  The toxicity of coal fly ash may pose potential health and safety risk to communities, workers, children, and adults who are exposed to it from its processing and during its foreseeable potential uses and disposal.  The Clean Air Task Force has published two reports discussing on the toxicity and harms of fly ash:

Laid to Waste: The Dirty Secret of Combustion Waste from America's Power Plants

Cradle to Grave: The Environmental Impacts from Coal

Without any toxicity testing requirements, highly toxic fly ash is exempted from regulation and is being used in building and consumer products without any labeling.  Fly ash added to cement may be used in foundations, walls, pools, heated and unheated floors and even countertops in schools, offices, and residences.  It may also be used in other  building materials including carpet, paint, shingles, acoustic ceiling tile, wall boards and stucco.   If CARB is to promote fly ash use in cement or other products then it should be very specific about what type of fly ash is permissible.    Currently there are no formal fly ash categories established and what little industry testing is conducted is used to characterize some engineering qualities and does not include any  California approved test methodologies or environmental or health hazard exposure testing.   If CARB is to promote and include fly ash use in cement or other products then it should define appropriate test procedures to limit toxicity to ensure that the public is safeguarded from potential exposures.  Additionally since cement is used as a structural material bearing loads CARB should fully investigate the recent findings acknowledged by the Coal Ash Association that some air pollution control devices result ash that when mixed with cement mixtures does not harden properly.  


More detailed information on fly ash toxicity, mercury content, and mercury mobility relatec to its potential exposure risks:

  1. Coal fly ash intrinsically contains specified amounts of mercury, and other heavy metals. Numerous studies and datasets show that coal fly ash contains quantities of mercury and other toxic compounds[7].   US EPA documents that mercury is emitted from coal burning power plants at a rate of 1.600E-5 Lb per Million BTUs Heat Input[8], [9].   In the US many studies have been funded through the Coal Ash Research Center (CARC) at the University of North Dakota[10] studying the mercury content of coal fly ash.  The Canadian Electricity Association (CAE) data indicates mercury concentrations ranging from <0.002 to 1.221 ppm in fly ash[11]. Hassett et al. reported mercury concentrations ranging from <0.01 to 2.41 ppm in samples of fly ash from full-scale coal-fired power plants from all ranks of U.S. coal[12], [13] , [14]. 
  2. Mercury (Hg) is a toxic compound that in its elemental inorganic form is a liquid at room temperature and is readily volatilized due to its vapor pressure.  As a result it represents a significant inhalation exposure risk. Mercury is listed as a persistent bio-accumulative toxic (PBT) compound and poses significant risk to human health for exposures that exceed daily regulatory limits.  Mercury and mercury compounds are on the list of chemicals known to the state of CA to cause reproductive toxicity.  OEHHA lists inorganic Hg and its compounds on CA?s chronic toxic compound list  and has a very low inhalation reference exposure level 0.09 mg/m3 and it is listed on OEHHA?s acute REL list with a Severe severity effect rating and is listed as having a reproductive/developmental toxicity endpoint[15].
  3. Coal fly ash also contains other heavy metals and significant quantities of crystalline silica, a human carcinogen.
  4. Fly ash is exempt from hazardous waste toxicity regulations by US EPA and is listed as a ?non-hazardous waste? for its end of life management.   US EPA however acknowledges that coal fly ash contains mercury and other quantities of toxics and  that the mercury can be potentially released into the air.  US EPA acknowledges that their new Clean Air Mercury Rule (CAMR) will result in significant reductions in mercury emissions from coal-fired power plants and may require assessment of mercury content in ash.  US EPA acknowledges on their website that the CAMR ??might affect the quantity of mercury in CCP (includes fly ash)??  And they indicate that they will reassess the issue if it appears that there is a significant increase in the level of mercury[16]. --CAMR is now actively being implemented in the US meanwhile we are waiting for their important assessment.  In the interim while US EPA completes its assessment there are no requirements to measure, limit or safeguard the public from potentially high mercury concentrations in coal fly ash used in cement or other consumer products.  
  5. Mercury concentrations in fly ash vary due to the variations in mercury found in the geological coal deposits and due to the different types of air pollution control systems installed at each coal burning power plant in the US.  
  6. The DOE/NETL in a memo dated April 2006 discusses some of the issues of mercury in coal fly ash.  DOE/NETL clearly recognizes that there are multiple means for mercury to be released from coal fly ash.  The research shows that mercury may be transported via aqueous transport via direct leachability, 2) vapor-phase release at ambient and elevated temperatures, and 3) biologically induced leachability.  Their research includes different testing protocols for each of these modes.  On page 4 it is confirmed that the environmental impact studies are not yet complete.  The 2005 memo states, ?DOE/NETL is carrying out research directed at evaluating the fate of mercury in coal combustion by-products and developing ways to ensure that the mercury is not released.? [17] 
  7. Release mechanisms of mercury from coal fly ash is complicated by the different mercury species that are inherent in coal fly ash and by chemical interactions that may occur within concrete -coal fly ash mixtures.
  8. EERC has studied the mercury content of a large number of coal combustion fly ash samples submitted by industry representing various types from different coal mining areas in the US.[18]  Mercury has been found to be released from coal fly ash into air at room and elevated temperatures.  Specifically, EERC studies have reported mercury releases from fly ash[19].     
  9. Importantly mercury was also found to be emitted from ash that is wet from water[20].  Experiments that included the addition of water to the samples exposed to air resulted in increases in the mercury flux.
  10. TCLP leach test data published in the literature for the tested coal fly ash samples indicates minimal leaching of mercury.  It might therefore be argued that concrete-ash mixtures are inert and non-reactive but leach tests do not directly address volatilization and mobility of mercury from concrete-ash mixtures into indoor air.  Leach tests are not emission tests and are designed only to look at aqueous leaching under landfill scenario and not classroom scenarios.  The mercury leach tests do not consider scenarios where there may be thin surface layers of moisture on concrete-ash mixtures nor do they consider chemical interactions from the case where concrete ash mixtures are used in combination with flooring adhesives for applications with resilient or carpet flooring.  What is missing from published literature is indoor air chamber test data to verify that there is are no toxic mercury emissions under the conditions of heat, moisture and combination contact with mastics coming off of the concrete/ash products?  Without this data there is no sound argument that these building materials are mercury emission free and safe for use. 
  11. Mercury quantities in coal fly ash vary because the quantity of mercury in coals burned vary and because power plants use different air pollution control devices which absorb varying quantities of mercury from the coal combustion.  On going statistical leach testing and emission testing for the full range of mercury coal fly ash quantities is needed to make generalities about all coal fly ash.    There presently is no voluntary screening testing conducted for quantification of mercury in coal ash to certify that it poses no threat of being released into the air or leached out.  Additionally, California has more stringent hazardous waste toxicity test leach tests called (STLC).  There is limited data available on the leaching of mercury under STLC testing.   Additionally Leach testing is designed to show that toxic compounds will not leach out of a landfill and pose threat to waterways, and is not an appropriate test to determine if it will be emitted into air when placed within building use scenarios.


Fly ash may contain Flue Gas Desulfurization (FGD) scrubbing sorbents:

  1. Many power plants have air pollution control devices installed.  Some use  injection of dry flue gas desulfurization sorbents to capture SO2 and NOx gas pollutants to maintain compliance with the NAAQS.  These powder sorbents are captured and mixed in with fly ash and included within compounds called fly ash.  
  2. EERC reports that calcium-based FGD systems are expected to remove oxidized mercury from flue gas at varying efficiency levels. Mercury has been found to be in fly ash FGD mixtures in concentrations of 39 and 70 ppm in sorbent materials that are mixed together in coal fly ash as reported by DeVito and Rosenhoover[21] and DeVito[22]  for two FGD materials.  Recently, the EERC reported that the mercury content of fly ash and FGD collected during tests of mercury control technologies are significantly increased;  samples containing a total mercury concentration as high as 120 ppm were reported. 
  3. The release of mercury from coal fly ash mixed with FGD has been evaluated on a limited basis.  Results of thermal desorption tests indicate that mercury is thermally released from sorbents at temperatures considerably below the peak temperatures observed for fly ashes. Significant percentages of the mercury captured on the saturated sorbents were reported to be released upon heating above 135°C (275°F).

Concrete reactions with adhesives and mastics:

  1. Documented studies showing that some adhesives used to secure carpet and flooring when in contact with concrete have resulted in concrete reactions and have facilitated migration of compounds in the concrete matrix despite claims that concrete is a pozzolonic inert material.  These studies confirmed volatile emissions from concrete.   Although theses studies do not provide any specific data about toxic emissions from concrete-ash mixtures or about mercury emissions they do provide important corollary information that concrete is NOT inert and has the potential to react with other substances and chemicals it comes in contact with and may emit toxics from its matrix into the air that may cause significant exposure risks to humans.  

Further Discussion and Conclusions

  1. Toxic compounds found in fly ash if mobilized may pose a serious threat to children and adults exposed.  The studies of the safety of concrete-coal fly ash mixtures are not yet complete and there is insufficient data showing that these materials do not emit toxics including mercury into environments where they are to be foreseeably used.  Since mercury, is a toxic compound for which exposures to children should be minimized it is best to take precaution and wait for studies to be conducted or commission screening tests such that decision to use these materials may be made with proper and adequate data before taking any action that might endanger the health and safety of children and the public in CA. What remains unanswered is whether or not the toxic compounds in concrete-coal fly ash mixtures are of high enough concentrations and sufficiently anchored into concrete under conditions of use proposed to prohibit them from being emitted into the air or otherwise absorbed by humans creating a significant risk.   Reviewing the literature indicates that there is a lack of sound scientific data to ascertain the level of risk of concrete mixed with coal fly ash.  One important criteria for building materials to be considered ?green? building materials is that they do not pose a toxic threat to occupants.  Testing and certifying that emissions are below health standards is important.  Current federal and state coal ash rules do NOT require mercury quantification or product emission testing for products using coal fly ash. 

More environmental impact tests are needed 

  1. It has been argued that ?Pozzolonic? forces in concrete coal fly ash mixtures are adequate to hold mercury within the concrete matrix and prevent it from being emitted into the air during use.  However there is minimal data to substantiate that concrete-coal fly ash mixtures subjected to moisture, heat, and cracking do not emit toxics including mercury. 
  2. The literature reveals that emissions of mercury ARE found for coal fly ash, and are potentially increasing due to the new CAMR requirements for mercury capture.    Precaution therefore should be taken.  Sufficient and adequate scientific information for concrete coal fly ash mixtures are needed to assure that its use in buildings and schools is safe.   Actions are needed to partner with the fly ash centers and industry groups to conduct emission testing and provide data on the vapor phase mobility of mercury and other toxics from flyash under foreseeable use scenario conditions of moisture, heat and contact with mastics used in applications on slab. 
  3. At a minimum CARB should institute the following conditional limits on the use of concrete fly ash mixtures:   
    1. Not to be used on surfaces where there is direct contact with children?s skin.  (ie gyms, pools, playgrounds, kindergarden rooms as flooring)
    2. Not to be used as a surface for food preparation
    3. Not to be used in combination with phthalate or soy based mastics or carpet backings in regions where flooding may occur or other high water intrusion probabilities exist. 
    4. not to be used where as an under floor or over floor surface for floor embedded heating pipes where high local temperatures might be experienced in the concrete-coal ash mixture. 

[7] XAFS investigation of Hg sorption on fly-ash , Hutton et al.  ,

For those unfamiliar, the toxics come from the coal itself and from the combustion process where they are contained or entrained in the particulate fly ash that is captured in flue gas air pollution control devices. 


[8] See US EPA?s WebFire database of emission factors,"">



[10]See the University of North Dakota?s website on Hg in CFA at,

[12] Hassett, D.J.; Pflughoeft-Hassett, D.F.; Laudal, D.L.; Pavlish, J.H. Mercury Release from

Coal Combustion By-Products to the Environment. In Proceedings of the Specialty

Conference on Mercury in the Environment: Minneapolis, MN, Sept. 15?17, 1999; Air and

Waste Management Association: Pittsburgh, PA, 1999; pp 485?493.

6. Hassett, D.J.; Heebink, L.V.; Pflughoeft-Hassett, D.F. Potential for Mercury Release from

Coal Combustion By-Products. In Proceedings of the Air Quality III: Mercury, Trace

Elements, and Particulate Matter Conference; Arlington, VA, Sept 9?12, 2002; Paper A2-


7. Pflughoeft-Hassett, D.F. Overview of EERC Studies in Evaluating CCR Products and

Identification of Major Data Gaps. Agenda for Coal Combustion Residues Workshop;

Research Triangle Park, New Jersey, January 10?11, 2001.

8. Zhenglong, L.; Hwang, J.Y. Mercury Distribution in Fly Ash Components. In Proceedings

of the Air and Waste Management Association 90th Annual Meeting and Exhibition;

Toronto, Ontario, Canada, June 8?13, 1997.





[19] Hasset et al. report Mercury release from fly ash from their experiments documented in their MERCURY AND AIR TOXIC ELEMENT IMPACTS OF COAL COMBUSTION BY-PRODUCT DISPOSAL AND UTILIZATION Final year Annual report for the U.S. Department of Energy

National Energy Technology Laboratory , June 2005,



[20] Gustin, M.S.; Ladwig, K. An Assessment of the Significance of Mercury Release from

Coal Fly Ash. J. Air Waste Manage. Assoc. 2004, 54, 320?330.


[21] DeVito, M.S.; Rosenhoover, W.A. Flue Gas Hg Measurements from Coal-Fired Boilers

Equipped with Wet Scrubbers. In Proceedings of the Air and Waste Management

Association 92nd Annual Meeting and Exhibition; St. Louis, MO, June 20?24, 1999.

[22] DeVito, M.S. The Effect of Low-NOx Burner Operation on Mercury Emissions,

Speciation, and Removal at a Coal-Fired Boiler Equipped with Wet FGD. Presented at the

17th Annual Pittsburgh Coal Conference, Pittsburgh, PA, Sept 11?14, 2000.

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