BREDL Comments on Tar Heel
Paving Draft Permit
March 12,
2001
Dr. Ernest Fuller
Division of Air Quality, Raleigh Regional Office
3800 Barrett Drive
Raleigh, NC 27609
Re: Tar Heel Paving, DRAFT Permit No.
08977R00
Dear Dr. Fuller:
I write to comment on the draft permit for Tar
Heel Paving in Henderson County. Based our
analysis and research done by experts in asphalt
plant air pollution, we recommend denial of this
permit. Further, we recommend that a statewide
epidemiological study be undertaken by the DAQ so
that we may better determine the health effects
of human exposure to asphalt fumes. Also, we
recommend that DAQ develop and implement noise
pollution control measures for all asphalt
plants.
Based on our experience working with residents
living near asphalt plants, we must conclude that
the skin rashes, difficulty breathing, asthma,
hypertension, and cancer clusters associated with
living near these plants constitute a public
health problem of unknown magnitude. It is hard
to believe that all these problems are due solely
to careless plant operators who lack concern for
their neighbors. Rather, it is the responsibility
of the state agencies charged with protecting
public health to take action to reduce known
sources of death and disease.
General Comments
Asphalt cement additives, higher
operating temperatures at small plants, and use
of recycled asphalt paving cause increases in
toxic emissions. These variables are not
accounted for in the EPA emissions data which is
used to permit asphalt plants. Further, the state
persists in utilizing inappropriate smokestack
models to predict ambient fugitive emission
levels.
The asphalt paving industry has dozens of
diluents and modifiers which are used to alter
asphalt properties. These additives include
plastic/rubber, rejuvenating oils, anti-stripping
agents, extenders and anti-oxidants. . These
additives change the volatility of the hot mix
asphalt product. These substances are added in
significant amounts: from one to several percent
by weight of the asphalt. It is important to note
that the recommended amount of additive exceeds
the typical volatiles content. According to
experts, these additives alter the vapor pressure
of the asphalt by increasing the volatility of
some of the lighter components which otherwise
might not have volatilized in the temperature
range of 275 to 375 degrees-F. EPA estimates of
volatiles content are based on asphalt cement
without additives and may bear little relation to
the emissions from asphalt paving practices in
North Carolina.
Another factor which increases asphalt fume
emissions is operating temperature. Emissions
increase exponentially with temperature. State
highway departments specify minimum and a maximum
temperature for HMA when delivered to the job
site where the pavement is being installed,
typically 275 to 325 degrees-F. Obviously, the
actual temperature of the asphalt loaded into a
truck is higher. Such restrictions do not apply
to HMA for non-state supervised jobs. Further,
private contractors will demand a higher
temperature at load-out since a smaller mass of
HMA will cool faster in smaller trucks
When a plant switches from one hot mix formula to
another emissions may increase. For example, a
plant using recycled asphalt pavement (RAP) has a
higher operating temperature to provide extra
heat to evaporate water associated with RAP,
since RAP is stored in the open. Switching to a
formula without RAP, the plant load-out will emit
a higher level of organics because of
overheating. Examples of this exist in the data
collected by the EPA at Plant C, a drum mix
plant, where emissions increased by a factor of 2
to 3 over a 40 minute period. Episodes of high
emissions caused by variations such as high
temperatures are missed by the total reliance on
averages of data collected under ideal test
conditions. The table below shows the effect of
different volatile contents and operating
temperatures on emissions.
Load Out
Emissions (a) |
EPA
(c) |
CITIZENS
(d) |
Total Particulate Matter |
104 |
515 |
Organic Particulate Matter |
68 |
478 |
Total Organic Compounds (Method 25A) |
832 |
5,836 |
Carbon Monoxide |
270 |
1,893 |
Silo filling
emissions (b) |
|
|
Total Particulate Matter |
117 |
423 |
Organic Particulate Matter |
51 |
356 |
Total Organic Compounds (Method 25A) |
2,437 |
17,100 |
Carbon Monoxide |
236 |
1,656 |
a) Load-out emissions for both
batch and drum plants - See AP-42, Table 11.1-14
(b) Load-out emissions for plants with silo
storage- mainly, but not exclusively, drum
plants. See AP-42, Table 11.1-14
(c) EPA estimates for drum plant in lb/200,000
tons of HMA. Volatility of 0.5%, 325 degrees-F
(d) Citizen estimates for drum plant in
lb/200,000 tons of HMA. Volatility of 1.0%, 375
degrees-F
The report (Attachment A) issued by citizens
groups after the issuance of EPAs fugitive
emissions test results states:
It can be seen that the emissions
calculated by using EPA-derived
equations, particularly emissions of
noxious organic compounds, increase by
over 600% under conditions of higher
operating temperature and volatility
contents. Both the EPA and the Citizen
numbers would increased by another 20 to
30% to compensate for the low bias
introduced by the background
correction and Method
204", discussed later in this
report. Finally, it should be noted that
although the numbers in Table 1 are shown
on an annual basis to help compare them
to Table 1 in the Executive Summary of
the Emission Assessment Report, the
citizens are aware that actual annual
emissions will be lower since a plant
will not always operate with an asphalt
with a high volatiles content at high
temperatures. On the other hand, the
table clearly shows the type of variation
in emissions that is likely to occur
under such conditions with its acute
effects on nearby residents.
Minority Report on Emissions from Asphalt
Plants, January 29, 2001, page 8
Based on reports from residents
in communities with operating asphalt plants, we
believe that periods of high emissions are
frequent. Further, the public health impacts of
these emissions are more significant since
asphalt plants in unzoned communities are located
closer to residential areas and small operators,
such as John Pace Enterprises, are more likely to
demand hotter asphalt. These emissions data are
even more significant in light of the already
high levels of PM-10, carbon monoxide, and
benzene emissions indicated by the DAQs
analysis of Tar Heel Paving.
Finally, the DAQs use of computerized
screening models for toxic, ground level
(fugitive) emissions remains troublesome because
such dispersion models do not apply within the
atmospheric boundary layer, a distance of 30 feet
from the ground where frictional effects
predominate (see Attachment B, Affidavit of Dr.
R. Nadkarni). This means that the use of such
models for fugitive emissions will predict more
dispersion and lower pollutant levels than will
actually occur. North Carolinas acceptable
ambient limits for toxics are designed to protect
human health, but the use of the dispersion model
in this case predicts the wrong ambient level.
Other air dispersion studies, based on average
factors from EPAs AP-42, show that ambient
air quality standards are often exceeded for
arsenic, cadmium and other heavy metals and for
organic chemicals such as benzene and
formaldehyde. With almost 2,000 dangerous
chemicals in asphalt fume, it is important that
the decision to build an asphalt plant in a
populated valley prone to inversions not be based
on a model which was developed solely for
smokestack emissions, not boundary layer fugitive
emissions. Because of the DAQs persistent
and inappropriate use of screen models for
fugitive emissions, we have little confidence in
the draft permits ability to protect public
health at this site.
Specific Comments
1) The permit will not control odorous emissions
Under Specific Conditions and Limitations, the
draft permit states,
As required by 15A NCAC 2D .0522
Control and Prohibition of Odorous
Emissions, the Permittee shall not
cause, allow, or permit any source to be
operated without employing suitable
measures for the control of nuisance
odors.
State law prohibits operation of a plant without
suitable measures to control odorous emissions.
The stated purpose of 2D .0522 is to
provide for the control and prohibition of
odorous emissions. [2D .0522 (a)]. It
states further that, This regulation shall
apply to all operations that produce odorous
emissions. [2D .0522 (b)] (emphases added).
Also, the DAQ Permit Review states that, No
facility shall emit odorous emissions without
suitable control measures. However, no
specific measures for the control of odor are
listed. As written, this draft permit fails to
stipulate measures for the control of odor.
Further, the Division has no objective means to
determine if the plant is in compliance with
permit requirements and the law. As a practical
matter, the DAQ inspector who might respond to a
plant neighbors complaint about odor would
have no means of enforcing this regulation. This
is an omission which must be corrected before any
air permit is issued.
2) Air pollution is underestimated
The draft permit lists regulated emission sources
ES-1 aggregate dryer; ES-2, ES-3, and ES-4 three
100-ton storage silos; and ES-5, ES-6, and ES-7
gravity-drop truck-loadouts. An attachment to the
permit also lists Activities Exempted from
Permitting Under 15A NCAC 2Q .0102. The
officially exempted sources include: 1) a No.2
fuel oil fired asphalt tank heater ES-8, and 2)
two 30,000 gallon fuel oil storage tanks ES-9 and
ES-10. The attachment acknowledges that the
asphalt tank heater and the storage tanks are
sources of toxic air pollutants and Title V
criteria pollutants. Omitted from the permit
exemption list are: 1) mobile sources of diesel
exhaust, 2) material handling and road dust, and
3) fugitive emissions from loaded trucks prior to
departure to the job site. A recent EPA report
lists all the above sources with corresponding
emissions of criteria pollutants and hazardous
air pollutants. I have attached Table 2 from the
December 2000 EPA Hot Mix Asphalt Plants Emission
Assessment Report to these remarks. The
DAQs omission of so many known air
pollution sources from the permit should be
corrected. The true total of toxic air emissions
should be included in the determination of
whether the plant meets the required acceptable
ambient limits.
3) Air Inversions and Pollution Trapping
Topography in area of Henderson County near the
proposed asphalt plant site ranges from about
2060 to 2600 feet amsl (Attachment C). An aerial
photograph taken over Henderson County
(Attachment D) reveals a surface inversion at
about 150 feet above the ground. High altitude
cloud cover was present on that day and is shown
in the photo. Cloud cover reduces sunlight and
heating of the surface which is the major way for
such inversions to be broken. Such conditions
could cause this inversion could persist into the
evening hours, and into the next day. This is,
perhaps, the worst case scenario for air
pollution in the valley along Muddy Creek. The
inversion traps the air from above, and hills and
mountains (Attachment E) trap it laterally. These
conditions are akin to an automobile with the
engine running in a room with the doors and
windows closed. No screening model used by North
Carolina is conservative enough to account for
these circumstances.
4) Noise Pollution is an Uncontrolled
Threat to Public Health
The problem with noise is that it negatively
affects human health and well-being. Problems
related to noise include hearing loss, stress,
high blood pressure, sleep loss, distraction and
lost productivity, and a general reduction in the
quality of life. While I can find no applicable
state statute or rule which applies to asphalt
plant noise, the close proximity to residential
areas in which the Tar Heel Paving plant would
operate requires an assessment of noise impact on
plant neighbors. The relevant example here would
be the Rhodes Brothers Paving plant in Macon
County which began operation in May 1999.
Since the plant commenced operation, residents
have reported effects associated with excess
noise including hypertension and anxiety. In a
letter to Macon County on December 22, 1999
(Attachment F), State Health Director Dennis
McBride states, OEE is concerned that
chronic exposure to noise, a stressor, emanating
from the Rhodes Brothers Asphalt Plant may have a
negative impact on the health of the Cullasaja
community over a long-term period.
If the Division of Air Quality proposes to issue
a permit for a plant which would create noise
levels high enough to damage public health, it
must take steps to ensure that the residents are
protected. It would be an inadequate response to
pass this off because noise is not a chemical
compound. According to NC Occupational and
Environmental Epidemiology Branch, the Rhodes
Brothers plant created noise levels of 66-70 dBA.
Dr. McBride stated that this exceeds the levels
specified by some local ordinances and the EPA.
The Commonwealth of Massachusetts Division of Air
Quality Control Policy states:
A source of sound will be
considered to be violating the
Department's noise regulation (310 CMR
7.10) if the source: Increases the
broadband sound level by more than 10
dB(A) above ambient, or Produces a
pure tone condition - when
any octave band center frequency sound
pressure level exceeds the two adjacent
center frequency sound pressure levels by
3 decibels or more. These criteria are
measured both at the property line and at
the nearest inhabited residence. Ambient
is defined as the background A-weighted
sound level that is exceeded 90% of the
time measured during equipment operating
hours. The ambient may also be
established by other means with the
consent of the Department.
North Carolina does not expect local governments
to adopt toxic air pollution rules; neither
should the state expect them to control noise
pollution from industrial plants permitted by the
Division of Air Quality.
Thank you for considering these remarks.
Respectfully submitted,
Louis Zeller
Attachments
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