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 http://www.arb.ca.gov/cc/ccea/ccea.htm
Tell CARB to remove this measure from their expanded
list,
http://www.arb.ca.gov/cc/ccea/meetings/091707workshop/ea_ii_report.pdf
(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:
- 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.
- ?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.
- 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:
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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 (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. Methane is about 21 times more powerful
at warming the atmosphere than CO2
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. 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. According to the American Coal Ash
Association, more than 71 million tons of fly ash are produced annually. 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 develop
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 http://www.catf.us/publications/reports/Laid_to_Waste.pdf
Cradle to Grave: The
Environmental Impacts from Coal http://www.catf.us/publications/reports/Cradle_to_Grave.pdf
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:
- 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. 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,
. In the US many studies have been
funded through the Coal Ash Research Center (CARC) at the University of North
Dakota
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.
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,
, .
- 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.
- Coal fly ash also contains
other heavy metals and significant quantities of crystalline silica, a
human carcinogen.
- 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. --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.
- 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.
- 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.?
- 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.
- 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. 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.
- Importantly mercury was also
found to be emitted from ash that is wet from water. Experiments that included the addition
of water to the samples exposed to air resulted in increases in the mercury
flux.
- 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.
- 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:
- 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.
- 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 and
DeVito 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.
- 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:
- 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
- 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
- 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.
- 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.
- At a minimum CARB should institute the following
conditional limits on the use of concrete fly ash mixtures:
- Not to be used on surfaces where there is direct contact
with children?s skin. (ie gyms,
pools, playgrounds, kindergarden rooms as flooring)
- Not to be used as a surface for food
preparation
- 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.
- 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.
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, http://www.undeerc.org/carrc/Assets/Yr2AnnualRpt.pdf
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.