NATIONAL AIR TOXICS INFORMATION
CLEARINGHOUSE NEWSLETTER	453N89003
A EDiA Office °' ^'r Quality Planning and Standards	December 1989
Research Triangle Park, North Carolina 27711
^crpry nET)rEr)/7\ fj /7\ ft M	State and Territorial Air Pollution Program Administrators
UZ-ALr u L-\ U i^liriZr-Au	Association of Local Air Pollution Control Officials
IN THIS ISSUE...
NATICH IS NOW LINKED TO TRIS	1
HARDCOPY REPORTS USEFUL, ACCORDING TO NEWSLETTER QUESTIONNAIRE	2
STATE/LOCAL AGENCY SPOTLIGHT* LOUISIANA BEGINS TO IMPLEMENT NEW
COMPREHENSIVE AIR TOXICS PROGRAM	2
STUDY TO EVALUATE ATMOSPHERIC DEPOSITION OF TOXIC CONTAMINANTS
TO PUGET SOUND UNDERWAY	3
A CASE STUDY FOR CARBON DISULFIDE: VIRGINIA FINDS VIOLATION OF
AIR TOXICS REGULATION		
EPA ISSUES GUIDANCE ON DATA QUALITY OBJECTIVES	5
CTC COMPLETES NEW AIR TOXICS REPORTS	5
NESCAUM RELEASES HEALTH EVALUATION OF GASOLINE VAPORS	6
EPA ISSUES POLICY DIRECTIVE ON AIR STRIPPERS AT SUPERFUND SITES	9
ALL STATES NOW ADDRESS AIR TOXICS, STAPPA/ALAPCO SURVEY FINDS	10
TAMS UPDATE: SYSTEM WILL REMAIN A RESEARCH VEHICLE	11
EPA MOVES TO REDUCE BENZENE AIR EMISSIONS	11
IMATICH IS NOW LINKED TO TRIS
State and local agency users of the NATICH data
base may now access industry emissions data located
in the Toxics Release Inventory System (TRIS)* through
a link that has been established between the NATICH
and TRIS data bases. These data bases both contain a
large volume of information related to air toxics. Thus,
the computer link is seen as a major step in integrating
information sources to the benefit of air pollution control
agencies.
TRIS was developed to make available information
that was submitted by industry under the provisions of
the Emergency Planning and Community Right to Know
Act. The information covers releases of over 300 toxic
chemicals to air, water, and land. Data include names
and addresses of facilities that manufacture, process, or
otherwise use the chemicals as well as amounts re-
leased to the environment or transferred to waste sites.
Data on stack and fugitive emissions to the air were
reported on over 70,000 forms for the 1987 reporting
year; data from the 1988 reporting year are currently be-
ing added.
Access to TRIS through NATICH is available only
to individuals working for State, local, and Federal agen-
cies. Public access to TRIS is available through the Na-
tional Library of Medicine. Call the Library at (301)
496-6193 or (800) 638-8480.
Once they have logged onto the NATICH system,
all State and local agency personnel with a computer ac-
count for NATICH are presented with a menu item that
enables them to access TRIS. Users may elect to use
programs that were developed by NATICH specifically
for air program activities, or programs developed by the
EPA Office of Toxic Substances to retrieve data from the
TRIS files. Once queries to TRIS have been completed,
the user is automatically returned to NATICH to enable
access to the complementary information on air toxics
contained there.
While the link simplifies data access, some
characteristics of the systems are slightly different. User
assistance is available through an information screen
describing these differences and steps to ensure
NATICH users a smooth transition as they access TRIS.
' —» ******

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Additionally, NATICH users may contact the Clear-
inghouse staff at (919) 541-0850 for assistance or to ob-
tain information on setting up NATICH accounts.
In addition to the TRIS link, a program has recently
been added to NATICH that enables users to retrieve all
of the information in the NATICH files on an individual
pollutant, source type or agency. This streamlines the
collection of information of interest, and sends the data
to remote printers distributed throughout the country. An
on-line option will be added soon to provide a list of the
remote printer locations in the user's State. Until that op-
tion is available, NATICH users not familiar with the
remote printer facilities may contact the National Com-
puter Center User Support group (919) 541-7862 on the
Clearinghouse Staff for further information.
* See related articles in May 1988 Newsletter, pp. 1 - 2,8.
HARDCOPY REPORTS US El
TO NEWSLETTER QUESTIO
Despite a small rate of return of the questionnaires
recently included in the NATICH Newsletter, certain
prevailing opinions have emerged. The Newsletter is
now sent regularly to approximately 2,000 subscribers;
of these, 35 percent are affiliated with State or local agen-
cies and another 32 percent are employed by industry
or as independent consultants. More than 50 percent of
those who returned the questionnaire are with State and
local agencies, accounting for more than 70 percent of
those who access the NATICH data online, and report-
ing the highest frequency of NATICH use. Hardcopy
reports of information were found useful across the
FUL, ACCORDING
iNNAIRE
board, but particularly by consultants and various en-
vironmental and special interest groups. Various other
reports were also well received and the frequency of
publication and/or updating was judged adequate for
most needs.
A majority of respondents have not used the
NATICH help line. However, of those who have used it,
most were satisfied with the assistance received.
Many respondents took time to make suggestions
for special reports. These have been tabulated and will
be useful to staff in selecting topics for future issues of
the Newsletter and for other publications.
STATE/LOCAL AGENCY SPC
LOUISIANA BEGINS TO IMI
COMPREHENSIVE AIR TO>
by Mike McDanlel, Assistant Secretary, Office off
Louisiana Department of Environmental Quality
Recognizing the magnitude of the air toxics prob-
lem within the State and the inadequacies of its existing
air toxics control program, the Louisiana Department of
Environmental Quality (DEQ) drafted a toxic air pollutant
emissions control bill, introduced in the 1989 regular ses-
sion of the State Legislature. In response to comments
from both industry representatives and environmen-
talists, the bill was refined to a form that was generally
acceptable to both, but still met the basic program ob-
jectives of DEQ. The bill then won unanimous approval
of both houses of the legislature and was signed into law
as Act 184 on June 23rd by Governor Buddy Roemer.
Act 184, The Comprehensive Toxic Air Emissions
Control Act, borrows language and some of its approach
from evolving Federal Clean Air Act legislation. It is
designed to use the basic concepts of the Federal air tox-
ics program while meeting the specific needs of the
State program. Act 184 is unique among State programs
in that its language is broad enough to address toxic
emissions from industrial, mobile, and area sources. It
#1 la
PLEMENT NEW
[ICS PROGRAM
Air Quality and Nuclear Energy,
r
also sets a goal and a time period for reductions in toxic
emissions, provides a means for measuring progress
toward attaining the goal, establishes reporting re-
quirements so that the public is informed of DEQ's prog-
ress, and provides a funding mechanism for the pro-
gram. Some of the more notable provisions of Act 184
are described below.
The new act defines "toxic air pollutant" in broader
terms than the old hazardous air pollutant definition,
reflecting contemporary definitions seen in developing
Federal legislation. According to Act 184, " 'toxic air
pollutant' means an air pollutant which, based on scien-
tifically accepted data, is known to cause or can
reasonably be anticipated to cause either directly or in-
directly through ambient concentrations, exposure
levels, bioaccumulation levels, or deposition levels,
adverse effects in humans, including but not limited to:
(i) cancer; (ii) mutagenic, teratogenic, or neurotoxic
effects; (iii) reproductive dysfunction; (iv) acute health
effects; and (v) chronic health effects."
2

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Act 184 requires the development of an initial list of
not more than 100 toxic air pollutants to be published by
December 31,1989. The DEQ is currently developing the
list, working from Superfund Amendments and
Reauthorization Act (SARA) industrial emissions data to
which mobile and area sources will be added. The list
will take into account relative toxicity, the populations ex-
posed, and environmental fate/effect information. The list
is to be ranked or classified according to level of concern
based on such criteria as emission levels, human health
effects, population exposure, and persistence or
accumulation in the environment. The list must be re-
viewed at least every 3 years and may be modified by
additions or deletions. Any person may petition to modify
the list.
The act addresses both new and existing sources.
Existing sources affected by the regulation will be
placed on compliance schedules. After completing the
pollutant list, DEQ will decide how to define a major
source, how to rank area sources, and what stationary,
mobile, and area sources to include.
The goal of the toxic air pollutant control program
is to reduce emissions of toxic air pollutants from all
sources by 50 percent from 1987 levels by December 31,
1994. It is an aggressive goal, but one that DEQ feels is
attainable without unreasonable economic impacts. A
guiding principle in the emissions reduction plan will be
to target those areas offering the greatest aggregate
reduction of health risks associated with populations ex-
posed to toxic air pollutant emissions.
To provide a benchmark or baseline against which
to measure progress in reducing emissions of toxic air
pollutants, Act 184 requires DEQ to conduct studies to
estimate emissions of toxic air pollutants from
industrial, area, and mobile sources, and publish a
report summarizing the baseline 1987 emission levels
by April 30, 1990. In April of each year thereafter, DEQ
must publish a report summarizing changes in emission
levels from the previously reported year and from the
1987 baseline levels, and documenting measures taken
and progress made toward reducing toxic air pollutant
emissions levels.
Act 184 requires that initial regulations for the con-
trol of toxic air pollutant emissions be proposed by July
1, 1990. The initial regulations will identify toxic air
pollutants to be regulated and establish a schedule for
the development of control measures for those
pollutants. The regulations will also seek to prevent sud-
den, accidental releases and minimize consequences
of any such releases.
The act requires monitoring of toxic air pollutants "at
locations and times deemed necessary" to further
develop information concerning sources and levels of ex-
posure to toxic air pollutants.
In several instances, Louisiana's new act directs that
information developed as a result of program efforts
"shall be made readily available to the public by the
Office of Air Quality and Nuclear Energy in an easily
accessible manner".
Finally, Act 184 provides DEQ with the authority to
levy and collect fees sufficient to fund the toxic air pollu-
tant emission control program and supporting ambient
air monitoring efforts. The DEQ is at work now outlining
a fee and permit system using Federal Clean Air Act
legislation as a guide.
For further information on the Louisiana air toxics
program, write Mike McDaniel at P.O. Box 44096,
Baton Rouge, LA 70804-4096, or call him at
(504) 342-1201.
STUDY TO EVALUATE ATM*
TOXIC CONTAMINANTS TO
by Naydene Maykut, Puget Sound Water Quality
An atmospheric deposition study is currently in
progress in the Commencement Bay watershed (near
Tacoma, Washington). The objective of this study is to
evaluate the importance of atmospheric deposition of
toxic contaminants to Puget Sound. Whether at-
mospheric deposition contributes toxic materials in con-
centrations high enough to harm the biota of Puget
Sound is an important scientific question and of poten-
tial regulatory interest. Knowledge of the toxic chemical
deposition pathway to Puget Sound will help direct future
research and management programs.
It is considered possible that the atmospheric
deposition of certain contaminants such as lead, arsenic,
polycyclic aromatic hydrocarbons (PAHs), and other
organic compounds may represent an important source
of pollutants to the Sound. Both lead and PAHs have
OSPHERIC DEPOSITION OF
PUGET SOUND UNDERWAY
Authority, Seattle, WA
been measured at levels of concern in both the
sediments and the sea-surface microlayer in several ur-
ban bays. More extensive studies in other parts of the
country have shown that atmospheric deposition is an
important source of particulate metals and PAHs in the
southern California Bight; a source of metals,
polychlorinated biphenyls, DDT, and other pesticides in
the Great Lakes region; and a source of nitrogen com-
pounds that contribute to serious eutrophication prob-
lems in Chesapeake Bay.
A sampling network was set up in Commencement
Bay consisting of five aerosol and deposition sites.
Two air deposition samples per month are being col-
lected at each of these five sites from July 1 to December
31,1989. A sixth sampler is collocated at various times
at each of the five sites to help verify the quality of the
3

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sampling data.
The aerosol sampling protocol is divided into two
different regimes: intensive and nonintensive. There are
two 5-week intensive sampling periods during the study;
one during primarily dry weather (July - August) and the
second during primarily wet weather (November -
December). Aerosol data are collected at three of the
sampling sites during the nonintensive parts of the study.
During the two intensive periods, aerosol sampling takes
place at all five primary sites. All aerosol samples will be
weighed for determination of total mass. A selected
number of aerosol and deposition samples will be
analyzed for metals and PAHs.
A modeling analysis will be used to correlate the
aerosol and deposition sampling results and to provide
a basis for future use of the results and methodology
throughout the Sound. Following are some important
areas that the modeling efforts will address:
-	Deposition of pollutants: the modeling effort will
produce maps of estimated target chemical
deposition in Commencement Bay and its
watershed;
-	Mobilization coefficients: estimates will be
made of toxic concentrations present in storm-
water runoff due to atmospheric deposition;
-	Chemical mass balance: estimates will be
made of the ratios of toxicants in the aerosol
samples contributed by the various air emission
sources, and the ratio of the air versus nonair
contribution of toxics to the sediments in
Commencement Bay; and
-	Synthesis of the data for final reporting.
Focusing efforts in the manner described above will
result in information and methodologies that can lead to
understanding the complexities involved in this research
area. For example, based on the results of this study, and
an institutional/regulatory analysis that will be included
in the final report, the Puget Sound Water Quality
Authority may decide to include programs in the 1991
Puget Sound Water Quality Management Plan that ad-
dress atmospheric deposition of toxic contaminants. The
Puget Sound Air Pollution Control Agency may also use
the results of this study to modify its air toxic program.
The final report is expected to be complete in May
1990. For additional information, please call Naydene
Maykut at (206) 464-6893.
A CASE STUDY FOR CARBC
FINDS VIOLATION OF AIR
by Charles Holmes, Air TdxIcs Program Coordlnat
The Virginia Department of Air Pollution Control (the
Department) recently performed an exhaustive evalua-
tion of the air emissions from Avtex Fibers Front Royal,
Inc., and found the emissions of carbon disulfide to be
in violation of the Commonwealth's regulations* Before
the Department began its action, Avtex was the world's
largest manufacturer of rayon and the only source of a
carbon yarn used by NASA and the Department of
Defense in rocket motor nozzles. Carbon disulfide is
used as a solvent in the fiber-forming process and is
emitted to the air without any reduction from control
devices. The emissions of carbon disulfide to the air
were reported at 49 million pounds per year, or 5,600
pounds per hour. Emissions of hydrogen sulfide,
dimethyl amine, ammonia, sulfuric acid, and lead were
also reported, but at much lower rates than carbon
disulfide. The magnitude of the emissions from Avtex
resulted in this facility being ranked number two in the
nation on the basis of total pounds of air emissions
reported for calendar year 1987, under SARA 313. In ad-
dition to the violation of air pollution regulations, Avtex
has been cited for water pollution and worker safety
violations, and this facility is an active Superfund site.
Virginia's existing Source Rule 4-3, Emission Stan-
dards for Noncriteria Pollutants, was the basis for the en-
forcement action against Avtex. This regulation provides
)N DISULFIDE: VIRGINIA
TOXICS REGULATION
or, Virginia Department of Air Pollution Control
for acceptable ambient limits (AAL) that are calculated
as a fraction (1/60 in this case) of the workplace
guidelines threshold limit values (TLVs) recommended
by the American Conference of Governmental Industrial
Hygienists. Virginia's AAL for carbon disulfide is 500
ug/m3 (0.167 ppm) averaged over a 24-hour period Ex-
tensive modeling was performed, including runs with
both Industrial Source Complex, Short-term (ISCST) and
COMPLEX I models. Over 50 release points were fac-
tored into the models; based on 5 years of meteorolo-
gical data, the predicted concentrations were calculated.
The models predicted concentrations of carbon disulfide
as high as 6,000 ug/m3 (24-hour averaging time), with
exceedances of the 500 ug/m3 AAL out to distances of
5 kilometers. The predicted exceedances of the AAL trig-
gered a requirement of one or more of the three options
available to the facility under this regulation. These three
options were:
(1)	Demonstrate that the facility does not and will
not cause or contribute to an exceedance of the
AAL,
(2)	Demonstrate that the AAL for the substance in
question is inappropriate by showing that the
emissions from the facility do not endanger
human health, or
4

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(3) Reduce emissions from the facility to a level
which does not result in an exceedance of the
AAL.
Avtex chose to demonstrate option two, no en-
dangerment of human health. Health effects testimony
on carbon disulfide was presented by consultants hired
by Avtex. For the Department, testimony was provided
by the State Health Department and the EPA's Air Risk
Information Support Center (Air RISC). The support pro-
vided by Air RISC was particularly useful, resulting in an
inhalation Risk Reference Dose for carbon disulfide. The
reference dose for carbon disulfide is 10 ug/m3, much
lower than Virginia's AAL of 500 ug/m3. While the
reference dose was not adopted as a revised AAL, it was
the single most important piece of health effects
evidence presented.
The State Air Pollution Control Board, a five-
member citizen board, held a formal hearing to consider
the hundreds of pages of testimony provided by Avtex
and the Department. In a 16-hour session, the Board
upheld the Department's recommendation and ordered
Avtex to submit a compliance plan within 2 months and
to achieve and demonstrate compliance within 1 year.
Avtex has filed an appeal to this Order in the Circuit Court
for the City of Richmond.
This enforcement action received national attention
since it coincided with the announcement of SARA 313
data by Representative Henry Waxman. The fact that
Avtex was the second most serious emitter of toxic air
pollutants in the nation also emphasized the importance
of this case. The company's strategic position as the sole
supplier of carbonized yarn to NASA and the Department
of Defense caught the attention of the national media.
Despite the threat of a significant loss of employ-
ment in Front Royal, there was widespread support for
the action of the State Air Pollution Control Board from
local citizens' groups, physicians at the community
hospital, and the Front Royal Town Council.
Virginia's air toxics regulations are currently
undergoing revisions that will result in a more efficient
and streamlined procedure. The Department is also
looking to incorporate a more widespread use of risk
assessment in its decision-making process. The Depart-
ment would welcome any ideas from other regulatory
agencies on what works and what does not. If you have
questions about the program or information on possible
improvements, please contact Charles Holmes, Air Tox-
ics Program Coordinator, Virginia Department of Air
Pollution Control, P.O. Box 10089, Richmond, Virginia
23240.
*Note: As of November 10, Avtex ceased all operations
in Front Royal as a consequence of revocation
of its National Pollution Discharge Elimination
System water discharge permit by the Virginia
State Water Control Board on November 8.
EPA ISSUES GUIDANCE ON I
An EPA document entitled "Guidance on Applying
the Data Quality Objectives Process for Ambient Air
Monitoring Around Superfund Sites (Stages I and II)" is
now available. This document should help readers
design an ambient air monitoring system that will be ade-
quate for the intended use of the data. It is intended to
serve as a bridge between the Quality Assurance
Management Staff's data quality objectives (DQO)
guidance and actual application of the DQO process at
Superfund sites. Specifically, this document was written
to aid the Remedial Project Managers, Enforcement
Project Managers, and the EPA Regional and Superfund
contractor personnel responsible for ambient air
>ATA QUALITY OBJECTIVES
sampling and analysis at Superfund sites to carry out
their duties efficiently and effectively.
This document gives an example of Stage I
(preliminary definition of the decision) and Stage II
(refinement of the decision and requirements) for
monitoring ambient air quality during remedial action at
a hypothetical Superfund site. Stage III of the DQO pro-
cess, to be completed in February 1990, involves the
design of an ambient air monitoring data collection
system for the case study presented in this document.
For further information or a copy of the document, call
Jane Leonard, EPA Technical Support Division at (919)
541-5653, (FTS) 629-5653.
CTC COMPLETES NEW AIR
The EPA's Control Technology Center (CTC) has
recently completed several projects dealing with
estimating air toxic emissions and evaluating control
techniques for a wide range of source categories. The
resulting documents cover surface impoundments, in-
tegrated steel plants, and waferboard plants.
The Surface Impoundment Modeling System
(SIMS) is a user-friendly PC program that can be a
TOXICS REPORTS
valuable tool when estimating emissions of volatile
organic compounds (VOCs) and air toxics. It can be
used on all types of surface impoundments or function-
ally similar wastewater treatment processes, including
biological treatment units. The program allows entry of
specific source information, but also provides industry-
based default values. Details of SIMS are included in a
user's manual and a technical support document that
5

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accompany the software.
In response to a request from the State of Utah and
EPA Region VIII, the CTC evaluated potential air toxics
emissions from integrated steel plants. The resulting
CTC report provides a comprehensive set of criteria and
toxic pollution emission factors for all source types com-
monly found at steel plants. It includes information on
process, fugitive, and nonpoint source emissions. A new
project to provide similar information for iron foundries
has been initiated and should be completed within 6
months.
A number of State agencies and EPA Regional
Offices asked the CTC to evaluate emission controls
from wood chip dryers and press vents at waferboard
manufacturing plants. These processes emit particulate
matter, formaldehyde, wood decomposition products,
and VOCs. The final report focuses on wet electrostatic
precipitator and electrified filter control systems and their
ability to adequately reduce these emissions.
The EPA and State and local air pollution control
agency staff should call the CTC HOTLINE at (919)
541-0800 or (FTS) 629-0800 for more information on
these new reports or to request CTC service. Others may
call Bob Blaszczak at (919) 541-5432 or Chuck Darvin at
(919) 541-7633 for more information.
NESCAUM RELEASES HEAI
OF GASOLINE VAPORS
by Margaret Round, Northeast States for Coordli
The Northeast States for Coordinated Air Use
Management (NESCAUM) has completed a report en-
titled "Evaluation of the Health Effects from Exposure
to Gasoline and Gasoline Vapors."
This report was initiated in response to the growing
concern in the Northeast over the known and potential
health effects of gasoline, especially as related to ex-
posure from gasoline service station operations and
from leaking underground storage tanks. This document
was developed as a tool for assisting States in their
management of gasoline-related health risks, and with
the expectation that its findings will be modified to ac-
commodate the various risk assessment and risk
management approaches that exist among the States
in the region.
The evaluation estimated exposure of service sta-
tion attendants, self-service customers, and nearby
residents to gasoline vapor emissions associated with
service station operations. Estimates were also deter-
mined for residents exposed to gasoline-contaminated
drinking water and gasoline vapors which have migrated
below ground into their houses from leaking
underground storage tanks. A review of the toxicological
data was conducted to assess the health significance of
these exposures. Because limited data exist regarding
the health effects from exposure to gasoline, the evalua-
tion also assessed the health impacts associated with
three constituents: benzene, toluene, and xylene.
Health criteria for cancer and noncancer effects
were based on the U.S. EPA cancer potency factors for
gasoline and benzene, and the most sensitive non-
cancer health effects identified by NESCAUM
associated with exposure to gasoline, benzene, toluene,
and xylene. These toxicity data were evaluated relative
to the six human exposure scenarios associated with en-
vironmental releases of gasoline in order to estimate the
.TH EVALUATION
nated Air Use Management
corresponding public health impacts (Table 1). Based on
this assessment, all scenarios pose cancer and non-
cancer risks from exposure to gasoline and/or three of
its constituents.
The document presents a qualitative discussion of
the major assumptions, uncertainties, and limitations of
this quantitative risk assessment. These considerations
must be taken into account when applying these data to
site-specific cases of exposure to gasoline vapors and
in the development of regulatory programs.
Report Approach Described
Standard risk assessment methods were adopted,
although it was necessary to modify them because of
limited toxicological data on the mixture and the variabili-
ty of the composition of the mixture after it is released
into the environment. This assessment of gasoline in-
cluded (1) studies on the entire mixture, (2) particular
fractions of the mixture, and (3) specific components
(benzene, toluene, and xylene) that were considered to
have the greatest health impacts.
The primary sources of data for refueling exposures
were monitoring studies of self-service customers and
service station attendants during refueling operations.
The exposure assessment accounted for exposure to
gasoline vapors both during refueling operations and
other time spent at the service station. In the case of
residential exposure, dispersion modeling was used to
estimate ambient concentrations from service station
emissions. Because conditions associated with leaking
underground storage tanks can vary significantly from
case to case, quantification of exposures was based on
limited case study information. Therefore, NESCAUM
points out that estimates for exposure and associated
risks for any given site need to be determined on a site-
specific basis.
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TABLE 1.


POTENTIAL NONCANCER RISKS ASSOCIATED WITH EXPOSURE TO GASOLINE AND SELECTED INDICATOR CONSTITUENTS
Estimated Exposure a
NESCAUM
Margin of Safety
Exposure (mg/kg/dayj
Reference Dose
(ref. dose/exp. dose)
Scenario mean maximum
(mg/kg/day)
mean
maximum
Scenario 1: self-service customer at gas station exposed via inhalation1,3


gasoline 9.4 x 10 1.0 x 10
0.003
0.32
0.03
benzene 7.3 x 10"5 7.2 x 10"4
0.004
55
5
toluene 5.7 x 10"6 4.9 x 10"4
0.0014
25
3
xylenes 2.2 x 10"5 2.6 x 10"4
0.034
1545
131
Scenario 2: gas station attendant exposed via inhalation1,3



gasoline 1.8
0.003
0.002

benzene 2.1 x 10"2 1.4 x 10"1
0.004
0.19
0.03
toluene 3.8 x 10'2
0.0014
0.04

xylenes 1.5 x 10'2
0.034
2

Scenario 3: resident living downwind of gas station exposed via inhalation1,3


gasoline 3.1 x 10 1.6 x 10
0.003
0.97
0.19
benzene 2.6 x 10"5 1.1 x 10"4
0.004
154
36
toluene 6.2 x 10"5 2.9 x 10'4
0.0014
23
5
xylenes 2.7 x 10'5 1.3 x10"4
0.034
1260
262
Scenario 4: resident inhaling vapors from nearby leaking underground storage tank1,4


gasoline
0.003
-
-
benzene 3.6x10"' 1.9
0.004
0.01
0.002
toluene 6.2 x 10"1 5.9
0.0014
0.002
0.0002
xylenes 4.2 x 10"1 3.6
0.034
0.08
0.0009
Scenario 5: resident exposed to gasoline via ingestion of contaminated well water2,4


gasoline 1.7x10 2.9
0.003
0.02
0.001
benzene 1.4 x 10"2 7.0 x 10"2
0.004
0.29
0.06
toluene 8.0 x 10'3 5.0 x 10"2
0.0014
0.18
0.03
xylenes 8.6 x 10"3 4.0 x 10"2
0.034
4
0.85
Scenario 6: resident exposed via inhalation and dermal contact during showering1,4,5


gasoline 1.7x10' 3.4x10
0.003
0.02
0.009
benzene 1.4 x 10"2 2.8 x 10'2
0.004
0.29
0.14
oluene 8.0 x 10'3 1.6 x10"2
0.0014
0.18
0.09
xylenes 8.6 x 10'3 1.7 x 10"2
0.034
4
2
a These calculations are presented in the report's exposure assessment chapter.


Assumes inhalation of 14.4 cu M/day, 24 h/day.



2 Assumes ingestion of 2L water/day.



Based upon arithmetic means of monitoring studies described in the report's exposure assessment chapter.

Based upon limited case-study information. Estimated risks for any given site need to be determined on a site-specific basis.
5 Assumes mean values equal mean drinking water exposures, and upper limits equal twice drinking water maxima.
Health Effects Identified
studies after protracted exposure to gasoline vapors
Acute exposure to gasoline and its components
were pulmonary toxicity and nephrotoxicity. Reproduc-
benzene, toluene, and xylene has been associated with
tive and developmental effects were among the most
skin and sensory irritation, central nervous system
sensitive noncancer toxic endpoints for benzene,
depression, and effects on the respiratory system. Pro-
toluene, and xylene exposures. These effects includ-
longed exposure to these compounds also affects these
ed increased resorptions, reduced fetal body weight,
organs as well as the kidney, liver, and blood systems.
and delayed skeletal development, and in the case of
In general, the effects that have been identified follow-
benzene, induced bone marrow suppression in off-
ing gasoline exposure were also identified for one or
spring.


more of the components of gasoline evaluated in this
With respect to carcinogenic effects, one adequate
assessment. For example, all substances have been
carcinogen bioassay for gasoline vapors was identified
shown to be neurotoxic and studies that indicated that
that reported statistically significant increases in kidney
gasoline is hematotoxic were supported in the assess-
tumors in male rats and hepatocellular tumors in mice.
ment by the abundant literature on benzene hematotox-
Major uncertainties were (1) the vapor composition in
icity. The primary effects reported in several animal
this study was different from the ambient human
7

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environment and (2) the kidney tumors observed in male
rats may be the result of a mechanism specific to the
male rat and not female rats or other species. Sufficient
evidence, however, was not available on the mechanism
of male rat kidney tumors to discount the positive car-
cinogenicity data from this bioassay. With respect to
benzene, an association between benzene exposure
and hematopoietic tumors has been found in
epidemiology studies. Thus, carcinogenicity of gasoline
and benzene was corroborated in more than one study,
by multiple routes of exposure, and in at least two
species of laboratory animals. It was the finding of
NESCAUM's evaluation that the animal and human data
provided sufficient evidence for presuming gasoline to
be a probable human carcinogen.
Risk Assessment Conducted
In NESCAUM's quantitative assessment for non-
cancer effects, critical studies were identified in the
areas of general toxicity, reproductive and developmen-
tal toxicity, and genetic toxicity. After the most sensitive
toxicological responses were identified, the studies most
appropriate for risk assessment based on study design
and toxicological relevance were selected for the risk
assessment. The most sensitive health effects
associated with gasoline, benzene, toluene, and xylene
were kidney toxicity (gasoline); developmental effects
(benzene); neurotoxic effects (toluene); and reproduc-
tive and fetotoxic effects (xylene).
Comparisons of human equivalent doses for the
lowest effect levels observed in animal studies showed
that sensitive toxicity endpoints for each substance
reviewed in this assessment (gasoline, benzene,
toluene, and xylene) are associated with fairly definable
dose ranges. For gasoline, kidney toxicity is associated
with human equivalent doses in the 2 to 4 mg/kg/day
dose range. For benzene, hematotoxicity occurs in the
dose range of 0.1 to 1.0 mg/kg/day. For toluene,
thresholds for sensitive neurobehavioral, hematological,
and immunological effects occur in the dose range of 0.5
to 1.5 mg/kg/day.
Risk Characterization Procedures Explained
Estimated cancer and noncancer risks for each of
the six scenarios were based upon comparison of health
criteria with estimated exposure doses. The health
criteria for cancer effects were cancer potency values;
the health criteria for noncancer effects were NESGAUM
reference doses. Several uncertainties were associated
with quantifying cancer and noncancer risks to humans
based upon data from animal bioassays and
epidemiological studies. These uncertainties included:
(1) estimates may exclude gasoline components of
potential concern; (2) inaccuracies in the assumptions
about the intensity and duration of exposure; (3) lack of
information on interactive effects among constituents in
the complex mixture, and (4) uncertainties associated
with exposure of sensitive individuals, including preg-
nant women, the very young, and the old or infirm, as
well as individuals who may suffer from chronic
respiratory, immunological, or other predisposing
illnesses. These and other uncertainties warranted the
adoption of conservative assumptions, when possible,
so that any errors were made on the side of caution. A
reflection of these uncertainties was provided in the
assessment by both average and upper limit exposure
doses and health criteria.
Noncancer health risks associated with gasoline ex-
posure are presented in Table 1. Both mean and worst-
case exposure assumptions yield estimates of exposure
doses that are greater than reference doses derived in
this assessment. Some margins of safety, however, ex-
ist with regard to specific indicator substances under all
scenarios.
Potential individual lifetime (70 years) cancer risks
associated with exposure to unleaded gasoline and
benzene were presented in the assessment. These
cancer risks were based on a cancer potency value of
0.0035 per mg/kg/day for gasoline and 0.026 mg/kg/day
for benzene. The exposure doses corresponding to one
in a million cancer risk for gasoline and benzene were
estimated to be 2.8 x 10"4 mg/kg/day and 3.8 x 10 s
mg/kg/day, respectively. Based upon an evaluation of
available data, toluene and xylene were assigned cancer
potency values of zero. Maximum individual lifetime
cancer risks associated with gasoline and/or benzene
are estimated below.
SCENARIO
MAXIMUM INDIVIDUAL
LIFETIME RISK(1>
Scenario 1
3.5 x 10"4<2)
Scenario 2
3.6 x 10'3(1)
Scenario 3
5.6 x 10"5(2>
Scenario 4
4.9 x 10'2(1)
Scenario 5
1.0 x 10"2(Z)
Scenario 6
1.1 X 103(z>
(1) Maximum individual lifetime risks based on max-
imum exposure to benzene.
(2) Maximum individual lifetime risks based on max-
imum exposure to gasoline (see Table 1 for exposure
doses).
It should be noted that although the exposure
doses for scenarios 4,5, and 6 were based on data from
limited case studies, significant risks may be associ-
ated with such exposures. Estimated risks for any given
site, however, need to be determined on a site-specific
basis.
Copies of the document are available from the
NESCAUM office. The price is $90.00 ($35.00 for
government or nonprofit agencies). For details,
please call Margaret Round, Toxics Coordinator,
NESCAUM, at (617) 367-8540.
8

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EPA ISSUES POLICY DIRECTIVE
ON AIR STRIPPERS
AT SUPERFUND SITES
Approximately 35 percent of the Superfund Records
of Decision signed to date have involved the use of a
pump-and-treat technique to either partially or fully
remediate ground-water contamination. Almost 45 per-
cent of these pump-and-treat sites have chosen air strip-
ping, a technique that uses volatilization to remove
volatile organic compounds (VOCs) from the ground
water. One known side effect of air stripping is that the
VOCs, many of which are toxic, are released to the am-
bient air. Control devices such as vapor carbon adsorp-
tion and incineration are used on 60 percent of the air
strippers to control these emissions, according to
analyses by EPA's Office of Emergency and Remedial
Response (OERR) and the Office of Air Quality Plan-
ning and Standards (OAQPS).
Despite a trend toward increased control of air emis-
sions from air strippers at Superfund sites, EPA remains
concerned with the control of these VOC emissions. This
concern is underlined by the vigorous efforts by EPA,
State, and local agencies, and industries across the
country to control air toxics and reduce VOC emissions
in ozone nonattainment areas. As a result of this con-
cern, OERR and OAQPS issued an OERR policy direc-
tive on June 15,1989, to provide guidance to the Super-
fund program on the control of VOC emissions from air
strippers at Superfund sites.
The policy directive states that for sites in ozone at-
tainment areas, the EPA Regions should continue to im-
plement Applicable or Relevant and Appropriate
Requirements (ARARs) which include State regulations,
risk management (i.e., protectiveness) guidelines, and
other requirements of Section 121 of the Comprehensive
Environmental Response, Compensation, and Liability
Act.
In ozone nonattainment areas, however, the
adoption of controls is more likely to be indicated even
if the controls are not mandated by current Federal or
State regulations or indicated by a cancer risk analysis.
Aside from their contributions to cancer risk, most
constituents of VOC emissions are precursors to the
formation of ozone. Consideration of these impacts
during remedy selection generally will show that
Superfund air strippers, except those with the lowest
emission rates, generally merit controls in nonattainment
areas.
In determining the need for air stripper controls at
a particular Superfund site in a nonattainment area, the
guidance indicates that the sources most in need of
controls are those with actual VOC emission rates in
excess of 3 pounds per hour, 15 pounds per day, or a
potential (i.e., calculated) rate of 10 tons per year. The
calculated rate assumes 24-hour operation, 365 days
per year. Control limits are applied on a facility basis.
For the purposes of this directive, "facility" is defined as
a contiguous piece of property under common
ownership.
The potential for applicability of the directive to other
VOC sources at Superfund sites is recognized. General-
ly, the guidelines described for air strippers are suitable
for VOC emissions from other vented extraction tech-
niques (e.g., soil vapor extraction) but not from area
sources (e.g., soils excavation).
The policy directive applies to future remedial deci-
sions at Superfund sites. It is not designed explicitly for
actions taken by the removal program in the case of
emergency or time-critical removal actions. However,
where time and other response circumstances permit,
such as for nontime-critical actions, adherence to the
directive is expected.
The control levels referred to in the directive serve
as guidelines only if ARARs do not exist or are less
stringent. They are not intended to preclude or replace
State proposals for more stringent levels of control in pur-
suit of the Clean Air Act goals as part of SIP revisions
in nonattainment areas.
The remedial investigation/feasibility studies of
Superfund sites should generate the data needed to sup-
port control decisions for both attainment and nonattain-
ment areas. At a minimum, the five major types of infor-
mation needed are:
-	Estimated cumulative uncontrolled air emis-
sions rate from all air strippers at the site,
-	Consideration of health risks from the execution
of the remedy as well as from the uncontrolled
site,
-	Control alternatives and their costs,
-	Ozone attainment status, and
-	Air ARARs.
For purposes of the policy directive "nonattainment
area" means any county included in a formal post-1987
ozone SIP deficiency notification (SIP call) or any other
county where the ozone National Ambient Air Quality
Standard (NAAQS) was exceeded during the previous
three-year period. EPA's initial SIP calls were issued pur-
suant to Section 110(a)(2)(H) of the Clean Air Act and
were described in the September 7, 1988, Federal
Register.
Questions concerning the policy directive should be
directed to Joe Padgett, U.S. EPA, OAQPS, at (919)
541-5589 or (FTS) 629-5589.
9

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ALL STATES NOW ADDRESS AIR TOXICS,
STAPPA/ALAPCO SURVEY FINDS
Many State and local air pollution control agencies
have developed or are now developing regulatory pro-
grams, which go beyond implementation of Federal
rules, to address toxic air pollutants. STAPPA/ALAPCO,
in a collaborative effort with the EPA's Air Quality
Management Division, recently surveyed 50 State and
220 local air pollution control agencies to determine the
extent of each agency's existing or planned program for
controlling toxic air pollutants. This survey updates one
conducted in 1984. The results of the 1989 survey are
compiled in a report entitled "Toxic Air Pollutants: State
and Local Regulatory Strategies - 1989."
The survey solicited information on all aspects of the
agencies' air toxics programs, including enabling legisla-
tion and administrative rules, program scope, control ap-
proaches, implementation mechanisms, collection of
toxic emissions data, level of agency effort, EPA
assistance, and the effect of SARA Title III on their pro-
grams. All 50 States and 40 local agencies responded
to the survey. Since all 50 States also responded to the
1984 survey, it is possible to assess the progress in State
air toxics program development that has occurred over
the past 5 years.
Air toxics control activity in the States has increased
significantly in the past 5 years. In 1984 only 19 States
had policies or regulations in place, and 23 had plans
to develop programs. Today, every State addresses air
toxics, either through a regulatory program (12 States),
comprehensive policy (22 States), or more informally
through New Source Review (16 States). Of the 40 local
agencies that responded to the survey, 16 have air tox-
ics programs in place for new sources and 11 are plan-
ning programs. In addition, four local agencies have
regulatory programs for existing sources and three have
comprehensive policies.
Most State and local agencies noted several
reasons for having a control program, the most common
being agency and public concern about health effects.
Many agencies also cited the need for prevention of
potential adverse health effects and EPA policy as
reasons for developing a program.
Not surprisingly, State and local agencies are
spending more time and money on their air toxics con-
trol programs than they were in 1984. Figure 1 illustrates
the number of work-years that States devoted to air tox-
ics activities in the past year compared to 1984. The me-
dian number of work-years States spent on air toxics is
5.4, compared to a median of 1 work-year in 1984. Local
agencies spent a median of 1.8 work-years on air toxics
in the past year. Out of six types of activities addressed
in the survey, most agencies spent the most amount of
time on permitting activities, and the least on enforce-
ment.
In 1984, the median annual spending level for State
agencies was $52,500. The 1989 survey indicated a me-
dian funding level of $330,000. Figure 2 illustrates the in-
crease in State funding from 1984 to 1989. The local
agencies that responded to the 1989 survey reported an
annual median funding level of $51,000. State agencies
reported spending the most money on monitoring ac-
tivities, while local agencies reported spending the most
on permitting. Typically, most State and local programs
are supported through a combination of their own funds
and Federal grants. Several agencies reported receiv-
ing a portion of their funding from operating permit fees
or inspection fees.
The agencies were also asked what type of
assistance they wished to receive from EPA for their air
toxics programs. The three highest priority areas cited
by both State and local agencies were the need for
health effects information, acceptable emission levels,
and control techniques.
More detailed information on these and many other
topics can be found in the complete compilation of the
survey results. In addition, a summary of the air toxics
program of each of the agencies that responded to the
survey is included in the document. For more informa-
tion on obtaining a copy of "Toxic Air Pollutants: State
and Local Regulatory Strategies-1989," contact
STAPPA/ALAPCO at (202)624-7864.
Figure 1. Comparison of State Agency Work Years
Devoted to Air Toxics -1984 versus 1989
Years (37)
5-10 Years (5)
1984
1989
Note: Number of Agencies Shown in Parentheses
Figure 2. Comparison of Annual Funding for State Air Toxics Programs
Number of States
1984
Number of States
1989
10

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TAMS UPDATE: SYSTEM Wl
A RESEARCH VEHICLE
Experience gained in Volatile Organic Compounds
(VOC) monitoring through the Toxic Air Monitoring
System (TAMS) has enabled other programs such as the
Urban Air Toxics Monitoring Program (UATMP) to pro-
vide routine monitoring to further the goals of urban air
toxics assessment. With the growth of the UATMP, the
TAMS was recently reassessed to consider the need for
field evaluation of polar compounds, semivolatiles, and
ozone precursors. Upon evaluation, it was concluded
that the TAMS should remain a research vehicle, and
that an orderly phase-out of some of the sites would be
necessary in order to explore monitoring methods for
these other pollutants. To accomplish these goals, the
LL REMAIN
number of sites was reduced from 10 to 4. Presently, the
TAMS consists of two sites each in Houston and Boston
where VOCs, polar compounds, semivolatiles, for-
maldehyde, and ozone precursor monitoring
methodologies can be explored.
Further information on the TAMS is available in the
form of status reports that are distributed on a regular
schedule. Additionally, a statement of the quality of data
needed to support specific programs, known as the data
quality objective, has been prepared for the TAMS.
For further information, call Jane Leonard, OAQPS,
Technical Support Division, at (919) 541-5653 or
(FTS) 629-5653.
EPA MOVES TO REDUCE Bl
In September, EPA finalized rules* expected to
result in 20,000 tons of reductions in emissions of
benzene** from industrial sources. The final regulations
require 97 percent emissions reductions from coke
byproduct recovery plants and also significant reduc-
tions from benzene storage tanks. In addition to its final
rules, EPA also proposed requirements for other major
benzene sources*** expected to result in an additional
reduction of 14,000 tons per year. In all, benzene emis-
sions would be reduced by 90 percent from current
levels.
A known human carcinogen, benzene is a major in-
dustrial chemical that has been linked to adult leukemia.
Benzene is used to manufacture a wide variety of prod-
ucts including plastics, insecticides, and polyurethane
foam. Benzene emissions are also present in automobile
exhaust, automobile refueling operations, cigarette
smoke, and many consumer products.
Exposure to emissions of benzene from these two
industrial sources represents an important long-term
health concern, particularly for those who live close to
major emitting facilities. Half the U.S. population is ex-
posed to these sources, which account for 20 percent
of the benzene emissions in this country.
The procedure used to establish the level of the
benzene emissions standards resulted from a 1987 court
decision (Natural Resources Defense Council v. EPA)
remanding to EPA earlier hazardous standards for vinyl
chloride. The court held that EPA should use a two-step
standard-setting process. First, the Agency must
establish a level of emissions that is considered safe or
acceptable based only on consideration of the potential
health impacts of exposure. In the second step, this level
may be reduced further upon consideration of control
cost or technical feasibility to provide an ample margin
of safety.
For the benzene source categories, EPA estab-
EIMZENE AIR EMISSIONS
lished a presumptive health benchmark for an unaccep-
table exposure level at a maximum individual lifetime risk
of developing cancer of 1 in 10,000. Although other
health risk measures and the inherent scientific and
technical uncertainties are considered in the decision of
what level of emissions is acceptable, the EPA's policy
is to ensure that few, if any, members of an exposed
population are exposed to levels at or above those
associated with a 1 in 10,000 lifetime risk. A secondary
goal is to ensure that as much of the exposed popula-
tion as possible does not face a lifetime risk greater than
one chance in one million. With the application of the
benzene rules, over 99 percent of the exposed popula-
tion would be below the one in one million lifetime risk.
In addition to the rules promulgated in September,
rules were proposed for several additional categories.
The proposed rules will achieve a 94 percent cut in
benzene emissions from railroad tank cars, trucks, boats,
and other transfer operations; a 95 percent reduction
from process vents in pharmaceutical manufacturing; a
75 percent reduction from rubber tire manufacturing; as
well as reductions from benzene waste operations and
reductions from gasoline terminals, plants, and service
stations.
The final and proposed rules represent EPA's first
hazardous air pollutant rulemaking since the landmark
1987 vinyl chloride ruling.
* National Emission Standards for Hazardous Air
Pollutants (NESHAP) 54 FR 38044, September
14, 1989.
** See related articles in September 1987 and May
1988 Newsletters.
*** Benzene waste operations including waste
water treatment; waste treatment, storage, and
disposal facilities; gasoline transfer operations;
gasoline marketing operations; and solvent use.
11

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CALL NEW CONTACT FOR SECTION 313
RISK SCREENING GUIDE
The September issue of the Newsletter an-
nounced that EPA's Section 313 "Toxic Chemical
Release Inventory Risk Screening Guide" is available.
The contact for the document has now changed. For ad-
ditional information on the Guide, write Lawrence S.
HELPFUL NUMBERS
Air Risk Information Support Center (Air RISC Hotline):	(919) 541-0888
	(FTSJ 629-0888
Control Technology Center (Hotline):	(919) 541-0800
	(FTS) 629-0800
NATICH Clearinghouse Staff:	(919) 541-0850
	(FTS) 629-0850
The National Air Toxics Information Clearinghouse Newsletter is published six times a year by the National Air Toxics Information Clear-
inghouse to assist State and local agencies making decisions on noncriteria pollutant emissions. The first issue appeared in December 1983.
The Clearinghouse is being implemented by the U.S. Environmental Protection Agency, Emission Standards Division, Pollutant Assessment Branch
as part of a joint effort with the State and Local Air Pollution Control Officials (ALAPCO). The National Air Toxics Information Clearinghouse Newsletter
is prepared by Radian Corporation under EPA Contract Number 68-D8-0065, Work Assignment 21. The EPA Project Officer is Scott Voorhees,
EPA Office of Air Quality Planning and Standards, Research Triangle Park, North Carolina 27711, Telephone: (919)541-5348. The Radian Project
Director is Caroline Brickley, P. O. Box 13000, Research Triangle Park, North Carolina 27709, (919)541-9100.
The Newsletter is prepared primarily for State and local air pollution control agencies and is distributed free of charge. Those wishing to
report address changes may do so by writing Meredith Haley, Radian Corporation, P. O. Box 13000, Research Triangle Park, North Carolina 27709.
Please contact the Project Officer either with any comments you might have pertaining to this newsletter or with suggestions for future newslet-
ters. Articles in the newsletter are written by Radian Corporation or EPA staff unless otherwise indicated.
The views expressed in the National Air Toxics Information Clearinghouse Newsletter do not necessarily reflect the views and policies of
the Environmental Protection Agency. Mention of trade names or commercial products does not constitute any endorsement or recommenda-
tion for use by EPA.
Rosenstein, Acting Director, Regional Risk Guidance
Staff, U.S. Environmental Protection Agency, (TS-778),
401 M Street S.W., Washington, DC 20460, or call
(202) 382-3628, (FTS) 382-3628.
Scott Voorhees
Pollutant Assessment Branch
U.S. Environmental Protection Agency
MD-13
Research Triangle Park, NC 27711
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