Journal of Environmental Protection, 2013, 4, 11-17
Published Online December 2013 (http://www.scirp.org/journal/jep)
http://dx.doi.org/10.4236/jep.2013.412A1002
Open Access JEP
Assessment of Public Health Risks Associated with
Naphthalene Entering Residences and Commercial Space
from Vapor Intrusion at MGP Sites*
Robin DeHate1,2#, Brian Skelly2, Marie Bourgeois1, Giffe Johnson1, Raymond Harbison1
1Center for Environmental/Occupational Risk Analysis and Management, College of Public Health, University of South Florida,
Tampa, USA; 2GEI Consultants Inc., Valrico, USA.
Received September 5th, 2013; revised October 7th, 2013; accepted November 9th, 2013
Copyright © 2013 Robin DeHate et al. This is an open access article distributed under the Creative Commons Attribution License,
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. In accor-
dance of the Creative Commons Attribution License all Copyrights © 2013 are reserved for SCIRP and the owner of the intellectual
property Robin DeHate et al. All Copyright © 2013 are guarded by law and by SCIRP as a guardian.
ABSTRACT
Naphthalene, a constituent of coal tar, is a contaminant frequently found at former manufactured gas plants (MGP).
Development at these sites has resulted in residential and commercial areas with potential exposures from vapor intru-
sion adversely affecting indoor air of residences and buildings. Naphthalene is routinely analyzed in soil vapor intrusion
assessments for properties overlying and surrounding former MGP sites. The United States Environmental Protection
Agency (EPA) has a proposed unit risk factor and the State of California has promulgated a unit risk factor for naphtha-
lene. Naphthalene exposure from vapor intrusion is potentially a public health risk. The purpose of this study was to
evaluate three sites located in the northeast United States to determine the frequency of naphthalene detection in indoor
air. A total of 79 properties were included in the study. A total of 546 indoor air samples were analyzed for naphthalene
on 161 occasions. Naphthalene concentrations ranged from 0.26 to 51 µg/m3 of air. Only 3 of the 546 indoor air sam-
ples detected naphthalene above the ninety-fifth percentile background value of 12 µg/m3 of air. Risk analysis indicated
naphthalene vapor intrusion was not a public health risk among the 79 properties built on or near the former MGP sites.
Keywords: Soil Vapor Intrusion; Naphthalene; Volatile Organic Compounds; Risk Assessment; Manufactured Gas
Plant
1. Introduction
Naphthalene is a polycyclic aromatic hydrocarbon (PAH)
that is found in coal and oil-derived materials and is of-
ten present in soil, water, and air at and around industrial
and manufactured gas plant (MGP) sites. Naphthalene is
a volatile organic compound frequently used as an indi-
cator chemical of potential manufactured gas plant (MGP)
contamination [1]. During the early 20th century, manu-
factured gas plants (MGP) were widely used for the pur-
pose of generating a local gas supply through the conver-
sion of coal into natural gas. The gasification of coal
generates coal tar, an oily compound containing multiple
volatile organic chemicals (VOCs) including benzene,
toluene, methylbenzenes, xylene isomers (BTEX) and
semi-volatile organic compounds (SVOCs) such as ace-
naphthene, acenaphthylene, naphthalene, phenanthrene,
phenols, and pyrene.
An estimated 1500 abandoned MGP sites in the US are
thought to present a potential public health hazard to the
surrounding properties redeveloped for commercial and
residential use. The United States Environmental Protec-
tion Agency is just one of many state and federal envi-
ronmental agencies that have recommended assessment
and remediation for the MGP sites [2]. The cost of reme-
diating these MGP sites may reach millions of dollars [3].
Since compounds like naphthalene may be present in
non-aqueous phase liquids (NAPL), the concern has ex-
panded from possible soil and groundwater contamina-
tion to the potential for soil vapor intrusion [4]. Inhala-
tion exposure via soil vapor intrusion to the chemicals
*Conflict of Interest: No authors have any competing interest related to
this research.
#Corresponding author.

Assessment of Public Health Risks Associated with Naphthalene Entering Residences and
Commercial Space from Vapor Intrusion at MGP Sites
12
commonly found at MGP sites is a concern because of
the potential for adverse effects on human health [5-9].
A major concern regarding the regulation of low level
naphthalene exposure is the issue of naphthalene’s poorly
characterized potential for carcinogenicity. The Naph-
thalene State-of-the-Science Symposium (NS3) in 2006
cites numerous issues in the regulation of naphthalene as
a carcinogen, including the lack high quality epidemiol-
ogical studies that support general causation between low
level naphthalene exposures and cancer in humans. This,
combined with the ubiquitous nature of naphthalene ex-
posure in outdoor air and common household products,
makes the regulation of low level naphthalene from
potential industrial contamination challenging [10].
The purpose of this study was to assess three aban-
doned MGP sites across the US Northeast for the poten-
tial of harmful soil vapor intrusion (SVI) of naphthalene
and to quantify the concentration of naphthalene if de-
tected. The results were analyzed to determine whether
naphthalene presented an appreciable human health risk
via soil vapor intrusion at the selected MGP sites. Regu-
latory guidance for the evaluation of low level naphtha-
lene exposures is also explored.
2. Methods
2.1. Site Evaluation
This study evaluated 79 properties, including commercial
and single family/multi-family residential properties with
potential naphthalene SVI from three former MGPs lo-
cated in the northeastern United States. These properties
were between 0 - 2500 feet of the plume or source mate-
rial at each site. The former MGP sites all overlaid per-
meable glacial outwash sands. The properties adjacent to
or overlying MGP tar source material and/or naphthalene
plumes were assessed for naphthalene SVI. Each of the
evaluated properties received potable water from mu-
nicipal sources. In order to assess the effect of depth to
groundwater on the SVI potential, each site was catego-
rized by vadose zone (region of aeration above the water
table): no vadose zone; water table within 6 feet of the
building slab (0 - 6 feet vadose zone); and water table
between 6 and 25 feet of the building slab (6 - 25 feet
vadose zone). The distance to the dissolved phase ground-
water plumes ranged from 2 to 35 feet below ground
surface (BGS).
Prior to assessing any possible vapor intrusion, a for-
mal analysis of structural factors (basement, crawl spaces,
etc.) that would contribute to the migration of soil vapor
was performed. A building survey and chemical inven-
tory was conducted to identify the presence or absence of
such factors. Naphthalene is present in multiple comer-
cial and consumer products (cigarettes, mothballs, insec-
ticides, etc.) so its presence is not indicative of SVI [11].
The existence of HVAC systems, fireplaces and clothes
dryers were included in the analysis as these can create a
pressure differential which may provide a pathway for
vapor intrusion.
2.2. Sample Collection and Analysis
Samples of indoor and ambient air were collected, in
addition to sub slab, proxy sub slab or soil vapor samples.
If they were present, groundwater samples were also
collected. Both indoor and soil vapor samples were gath-
ered using Summa or equivalent canisters. Each soil
vapor sample point was sampled beneath an enclosure
enriched with helium gas to evaluate potential infiltration
of ambient air during the collection of the soil vapor
sample. Helium was not detected within soil vapor sam-
ples verifying the integrity of the soil vapor probe seal at
the time of sampling and that the soil vapor samples were
representative of subsurface conditions [1].
Sub-slab soil vapor samples were collected in those
properties with a vadose zone detected beneath the bui-
lding slab. Soil vapor samples were collected beneath
surrogate caps such as a driveway or patio when the wa-
ter table was present above the basement slab. Indoor air
samples were collected in those properties without a va-
dose zone. The majority of the samples were collected
from November 15 to March 31 to coincide with heating
season in the northeastern United States.
2.3. Risk Assessment
Data from 546 indoor air samples were analyzed for
naphthalene in accordance with USEPA method TO-14A
or TO-15. An independent reviewer validated all ana-
lytical laboratory results. As previously described in
DeHate, et al. 2011, this method directs a known volume
of sample through a multisorbent concentrator [1]. Water
vapor from the sample breaks through the concentrator.
The amount of vapor is dependent upon sampling dura-
tion and concentrator composition. After concentration
and drying are complete, the naphthalene is desorbed,
entrained and focused using a small volume multisorbent
or reduced temperature trap.
The samples are thermally desorbed and separated via
gas chromatography. Helium is used as a tracer gas to
verify the integrity of the soil vapor probe seal and en-
sured the samples were representative of the subsurface
conditions. Analysis was conducted by Alpha Woods
Hole in Westborough, Massachusetts, a New York State
Department of Health approved laboratory for identifica-
tion and quantification of sample constituents using high
resolution gas chromatography (GC) and mass spectros-
Open Access JEP

Assessment of Public Health Risks Associated with Naphthalene Entering Residences and
Commercial Space from Vapor Intrusion at MGP Sites
13
copy. Helium analysis was conducted using the Ameri-
can Society for Testing and Materials (ASTM) Method
1946. This data was then compared to both regulatory
and proposed guidance values for health risk to draw
inferences as to the safety of the exposures observed.
3. Results
3.1. Exposure Assessment
The comparative data base used in this study as back-
ground values was the New York State Department of
Health (NYSDOH) Guidance for Evaluating Soil Vapor
Intrusion in the State of New York, 2006. Appendix C of
this document contained the NYSDOH 1997: Control
Home Database. From 1989-1996, the NYSDOH col-
lected 228 indoor and outdoor air samples from 53 resi-
dences used as control homes in New York State inves-
tigations. In this study control homes were defined and
selected to represent homes with neighborhood, con-
struction, and occupancy similar to homes being investi-
gated for VOC impacts on indoor air. Control homes also
had no unusual source of VOCs, such as past oil spill,
recent refinishing or painting activities, or proximity to
the VOC source being investigated. This data set con-
tains the comparative values for naphthalene used in our
study.
Sites A, B and C properties are described in Table 1.
Nearly all of the obtained naphthalene concentrations fell
within the background concentration range. Detected
naphthalene concentrations ranged from 0.26 to 51 µg/m3.
Three of the 546 indoor air samples detected naphthalene
above the 95th percentile background value of 12 µg/m3.
All three of these detections were associated with Site A.
Overall, naphthalene was detected in less than 1% of the
546 indoor air samples.
A critical review was conducted of the three sites
where naphthalene was detected above background lev-
els. One of these detections was determined to be the
result of a consumer product containing naphthalene
(mothballs) that was present in the residence, rather than
SVI. At a second property, naphthalene was detected in a
sump room air sample where impacted sump water was
present. Naphthalene was not detected in seventy-one
other samples taken at the same location during six sepa-
rate sessions. Naphthalene was also detected in a sample
from the second floor of the building. Seven other sam-
ples collected at the same property failed to detect naph-
thalene in the soil vapor or in the indoor air on the first
floor.
We were unable to obtain the actual data set from the
NYSDOH, so we compared the concentrations from our
sites to the percentile categories from the NYDOH sum-
mary tables. Figures 1-3 describe the percent of concen-
Table 1. Summary of data collected at evaluated sites.
Site A Site B Site CTotal
Number of properties 66 6 7 79
Number of events 143 9 9 161
Number of samples 508 22 16 546
Minimum detection (µg/m3) 0.26 0.26 0.42
Maximum detection (µg/m3) 51 7.8 2.1
Number exceeding 12 (µg/m3) 3 0 0 3
(<2
μg/m3)
(<10
μg/m3)
(<10
μg/m3)
(<12
μg/m3)
Figure 1. Results at Site A by quartile compared to NYS-
DOH indoor background level quartiles.
(<2
μg/m3)
(<10
μg/m3)
(<10
μg/m3)
(<12
μg/m3)
Figure 2. Results at Site B by quartile compared to NYS-
DOH indoor background level quartiles.
(<2μg/m
3
)(<10μg/m
3
)(<10μg/m
3
)(<12μg/m
3
)
Figure 3. Results at Site C by quartile compared to NYS-
DOH indoor background level quartiles.
Open Access JEP

Assessment of Public Health Risks Associated with Naphthalene Entering Residences and
Commercial Space from Vapor Intrusion at MGP Sites
Open Access JEP
14
trations at each site measured above the 25th, 50th, 75th,
and 95th percentile concentration in the NYSDOH sum-
mary tables. Figures 1-3 show that fewer samples in our
data set exceed the NYSDOH percentile concentrations;
meaning our site data was centered around lower con-
centrations of naphthalene than that of the NYSDOH
data set.
3.2. Risk Assessment
Using the Unit Risk Factors of 1E-04 and 3.4E-05
(promulgated by the USEPA and the OEHHA of the
State of California, respectively) in conjunction with the
ambient naphthalene concentrations set forth by ATSDR,
the risks are calculated and shown in Table 2. Most of
these values exceed the USEPA acceptable risk range
(1E-04 to 1E-06) and all exceed the acceptable risk set
forth by states with more conservative values (1E-05; CA,
MA). Similar results have previously been published for
ambient air benzene levels; i.e . the generation of theo-
retical risk values in excess of regulatory limits for back-
ground exposures [12].
4. Discussion
This study assessed the potential public health risks
posed by soil vapor intrusion from naphthalene contami-
nation at residential and commercial properties abutting
and overlying former MGP sites. Actually measuring
indoor exposures provided valuable data as predictive
models based on attenuation factors may be subject to
large degrees of variability in their predictive value [13].
As previously stated, naphthalene was detected in less
than 1% of the indoor samples, indicating negligible
public health risk from naphthalene vapor intrusion im-
pacting indoor air in the 76 properties built on or near the
former MGP sites. Additionally, only 3 of the 546 indoor
air samples registered naphthalene concentrations above
the ninety-fifth percentile background value of 12 µg/m3
of air. These 3 detections could be explained by sources
of naphthalene other than soil vapor intrusion from the
former MGP sites. Overall, the measurements are con-
sistent with other investigations of background levels of
indoor naphthalene that typically range from 0.89 µg/m3
to 3 µg/m3, occasionally ranging as high as 200 µg/m3
[14].
The majority of the buildings and residences in this
study were built in the late 1950s to early 1960s; how-
ever some of these buildings were over 100 years old.
The residential buildings were primarily wood frame
over a concrete foundation and a basement. Several of
the structures included crawl spaces and basements with
soil rather than concrete floors. The commercial build-
ings were generally concrete block with concrete founda-
tions and basements. The majority of the structures as-
sessed used sumps to capture groundwater under and
around basements. Age and construction type of the
buildings appeared to have limited impact on SVI. Fac-
tors such as natural attenuation and a protective layer of
clean groundwater between the building and the naph-
thalene plume can act to mitigate SVI. Though internal
building pressure is known to affect the potential for va-
por intrusion, this did not appear to be a factor in this
study [15]. Additionally, some bacteria use contaminants
as a carbon source reducing or sometimes even eliminat-
ing the VOCs available for SVI [16]. It is likely that the
substantive exposures measured in this study are a result
of background exposure and consumer product use rather
than contamination from former MGP activity.
According to the International Agency for Research on
Cancer (IARC) and the National Toxicology Program
(NTP), naphthalene is reasonably anticipated to be a hu-
man carcinogen [17,18]. This conclusion is currently
being evaluated by the USEPA, ATSDR and other fed-
eral agencies. The USEPA has published a document
entitled “External Review Draft Toxicological Review of
Naphthalene—In Support of Summary Information on
the Integrated Risk Information System (IRIS) (“Draft
Review”). This document sets forth proposed information
Table 2. Carcinogen risks for various concentrations of naphthalene calculated with USEPA methodology.
Naphthalene concentration
range (µg/m3) Location Outdoors/Indoors
EPA Risk
Level/Range
CAL EPA Risk
Level/ Range
1 Urban Household Indoors (Nonsmoking Household)1E−04 3.4E−05
2.2 Urban Household Indoors (Smoking Household) 2.2E−04 7.5E−05
0.4 - 170 11 US Urban Cities Outdoors 4E−05 - 1.7E−02 1.4E−05 - 5.8E−03
0.94 11 US Urban Cities Outdoors (median range) 9.4E−05 3.2E−05
0.33-9.7 North Carolina Low Income HomesIndoors 3.3E−05 - 9.7E−04 1.2E−05 - 3.3E−04
0.57 - 1.82 North Carolina Low Income HomesOutdoors 5.7E−05 - 1.82E−05 1.9E−05 - 6.2E−05
0.42 - 4.6 New Jersey Outdoors 4.2E−05 - 4.6E−04 1.4E−05 - 1.6E−04

Assessment of Public Health Risks Associated with Naphthalene Entering Residences and
Commercial Space from Vapor Intrusion at MGP Sites
15
for updating IRIS’ entry on naphthalene. Since USEPA’s
IRIS database is a primary tool used by federal and state
regulators to establish site remediation requirements, the
Agency’s on-going review and proposed revisions to
IRIS will likely influence how naphthalene is regulated,
manufactured, and utilized in the future.
According to this document, naphthalene is carcino-
genic, and the proposed toxicity values may decrease
both residential and industrial soil screening concentra-
tions (Regions III RBC and 9 PRG) by an order of mag-
nitude or greater. Additionally, this document indicates
that groundwater and SVI values would exceed those
found in urban fills and natural soils. As a result, this
publication carries serious implications for the investi-
gation and cleanup requirements of MGP sites. Three
regulations carry particular implications: 1) where site
soil has already been remediated and the owner must
evaluate the potential impacts of remaining concentra-
tions and the prospect of future regulatory action; 2)
where site soil is still in the assessment or remedial de-
sign phase; and 3) where groundwater concerns must be
addressed [19].
The USEPA has promulgated a draft unit risk factor
(URF) for naphthalene of 1E-04 per µg/m3 of exposure.
The Office of Environmental Health Hazard Assessment
(OEHHA) of the State of California has set a unit risk
factor of 3.4 E-05 per µg/m3 for the evaluation of human
health risks at contaminated sites. These risk levels are
considered upper end, mostly due to the fact that: 1) cur-
rent laboratory analyses for air samples rarely provide
detection limits in the sub-ppb range; 2) estimations of
risk from ambient exposures to naphthalene in both in-
door and outdoor air result in risks to humans above
regulatory guidelines; and 3) with the historic omnipres-
ence of naphthalene use as both an industrial and domes-
tic pesticide, a clear association between naphthalene
exposures and human cancers should have been eluci-
dated, however, evaluation by ATSDR (2005) has main-
tained that no cohort or morbidity studies have been
identified to establish naphthalene as a human carcinogen
[20].
These proposed changes to risk evaluation are based
on NTP bioassay data relevant to exposures several or-
ders of magnitude higher than environmental exposures
and limited epidemiological data pertinent to assessing
naphthalene carcinogenicity, which are generally viewed
as inadequate for determining human carcinogenicity of
naphthalene [17,18,21]. Price and Jayjock (2008) com-
pared the exposures from the NTP bioassay results that
induced cancer in animals to background exposures and
found that the bioassay levels were 3000 - 10,000 times
higher than the levels of exposure received from ambient
air [22]. As well, levels of exposure for individuals in
homes using mothballs are still 10- to 100-fold lower
than the levels used in the bioassay. This is consistent
with the results of the current study which found a
maximal exposure of 51 µg/m3, and a total of 3 meas-
urements of 546 greater than 12 µg/m3 which can be
compared to the exposures of 52,400 - 314,400 µg/m3 for
respiratory epithelial adenomas in male rats, olfactory
epithelial neuroblastomas in female rats, and pulmonary
bronchial adenomas in female mice [23,24].
Not only do the exposures measured in this study fall
substantially below exposures necessary to produce can-
cer in animals, the absence of reliable epidemiological
data raises a fundamental question regarding the rele-
vancy of the animal findings to carcinogenicity in hu-
mans. Some factors in question include increased lung
metabolism in rodents in a study that was dependent on a
saturated metabolic system, the potential for species
specific metabolism in the rat nasal olfactory epithelium,
differential nasal passage anatomy between rats and hu-
mans, and the use of a maximum tolerated dose approach,
which may not adequately characterize lower dose me-
chanisms of carcinogenesis if they are present [25].
Additional researches to better compare the cross-spe-
cies metabolic activities and to assess impacts at lower
exposure levels to better define any dose-response rela-
tionship is ongoing among regulatory agencies. A reas-
sessment of the toxicological potential of naphthalene
may lead to significantly altered regulatory requirements
applicable to the manufacture, use, management, and
disposal of naphthalene. It will be important to rely on
data that adequately characterizes risk from relevant en-
vironmental and occupational exposure levels to prevent
the gross overestimation of risk of low level naphthalene
exposure, putting background levels into the range of
non-compliance. The results from this study indicate that
naphthalene exposures from previous MGP sites are
similar to background exposures and exposures from use
of common household products. If naphthalene were to
become the primary risk driver at previous MGP sites, it
may produce the untoward effect of increasing cleanup
costs without benefit to the public health.
5. Conclusion
Based on the results of this study, naphthalene did not
present a health risk via soil vapor intrusion for the hu-
man population surrounding these former MGP sites.
MGP associated vapors would need to permeate through
several pathways into residential and commercial build-
ings in order to accumulate in sufficient concentrations to
present an unacceptable risk to human health. If naph-
thalene was detected in buildings and residences, it was
due to a combination of background naphthalene, vola-
Open Access JEP

Assessment of Public Health Risks Associated with Naphthalene Entering Residences and
Commercial Space from Vapor Intrusion at MGP Sites
16
tilization from contaminated groundwater, and use of
consumer products containing naphthalene.
6. Acknowledgements
This study was supported in part by GEI Consultants Inc.
and the Center for Occupational/Environmental Risk Ana-
lysis and Management, College of Public Health, Uni-
versity of South Florida, Tampa, Florida.
REFERENCES
[1] R. B. DeHate, G. T. Johnson and R. D. Harbison, “Risk
Characterization of Vapor Intrusion in Former Manufac-
tured Gas Plant Sites,” Regulatory Toxicology and Phar-
macology, Vol. 59, No. 2, 2011, pp. 353-359.
http://dx.doi.org/10.1016/j.yrtph.2010.12.001
[2] United States Environmental Protection Agency, “Com-
pendium of Methods for the Determination of Toxic Or-
ganic Compounds in Ambient Air, 2nd Edition, Compen-
dium Method TO-15 Determination of Volatile Organic
Compounds (VOCs),” Air Collected in Specially-Pre-
pared Canisters and Analyzed by Gas Chromatography/
Mass Spectrometry (GC/MS), Center for Environmental
Research Information, Office of Research and Develop-
ment, Cincinnati, 1999.
[3] Electric Power Research Institute, “50 MGP Site Man-
agement Portfolio,” Federal Register, Vol. 77, No. 88,
2008, pp. 26751-26755.
[4] L. Turczynowicz and N. I. Robinson, “Exposure Assess-
ment Modeling for Volatiles—Towards an Australian in-
door vapor intrusion model,” Journal of Toxicology and
Environmental Health, Part A, Vol. 70, No. 19, 2007, pp.
1619-1634.
http://dx.doi.org/10.1080/15287390701434711
[5] D. J. Vorhees, W. H. Weisman and J. B. Gustafson, “Hu-
man Health-Risk Based Evaluation of Petroleum Re-
lease Sites: Implementing the Working Group Approach,”
Total Petroleum Hydrocarbon Criteria Working Group,
Vol. 5, Amherst Scientific Publishers, Amherst, 1999.
[6] T. E. McHugh, L. Beckley, D. Bailey, K. Gorder, E. Det-
tenmaier, I. Rivera-Duarte, S. Brock and I. C. Mac-
Gregor, “Evaluation of Vapor Intrusion Using Controlled
Building Pressure,” Environmental Science & Technol-
ogy, Vol. 46, No. 9, 2012, pp. 4792-4799.
http://dx.doi.org/10.1021/es204483g
[7] G. J. Kullman and R. A. Hill, “Indoor Air Quality Af-
fected by Abandoned Gasoline Tanks,” Applied Occupa-
tional and Environmental Hygiene, Vol. 5, No. 1, 1990,
pp. 36-37.
http://dx.doi.org/10.1080/1047322X.1990.10389585
[8] M. L. Fischer, A. J. Bentley, K. A. Dunkin, A. T. Hodg-
son, W. W. Nazaroff, R. G. Sextro and J. M. Daisey,
“Factors Affecting Indoor Air Concentrations of Volatile
Organic Compounds at a Site of Subsurface Gasoline
Contamination,” Environmental Science & Technology,
Vol. 30, No. 10, 1996, pp. 2948-2957.
http://dx.doi.org/10.1021/es950912e
[9] C. L. Moseley and M. R. Meyer, “Petroleum Contamina-
tion of an Elementary School: A Case History Involving
Air, Soil-Gas, and Groundwater Monitoring,” Environ-
mental Science & Technology, Vol. 26, No. 1, 1992, pp.
185-192. http://dx.doi.org/10.1021/es00025a023
[10] F. Y. Griego, K. T. Bogen, P. S. Price and D. L. Weed,
“Exposure, Epidemiology and Human Cancer Incidence
of Naphthalene,” Regulatory Toxicology and Pharmaco-
logy, Vol. 51, No. 2, 2008, pp. S22-S26.
http://dx.doi.org/10.1016/j.yrtph.2008.02.003
[11] P. C. Johnson, R. A. Ettinger, J. Kurtz, R. Bryan and J. E.
Kester, “Migration of Soil Gas Vapors to Indoor Air: De-
termining Vapor Attenuation Factors Using a Screening-
Level Model and Field Data from the Cdot-Mtl Denver,”
Colorado Site, American Petroleum Institute, 2002.
[12] G. T. Johnson, S. C. Harbison, J. D. McCluskey and R. D.
Harbison, “Characterization of Cancer Risk from Air-
borne Benzene Exposure,” Regulatory Toxicology and
Pharmacology, Vol. 55, No. 3, 2009, pp. 361-366.
http://dx.doi.org/10.1016/j.yrtph.2009.08.008
[13] Y. Yao, R. Shen, K. G. Pennell and E. M. Suuberg, “Ex-
amination of the Influence of Environmental Factors on
Contaminant Vapor Concentration Attenuation Factors
Using the U.S. EPA’s Vapor Intrusion Database,” Envi-
ronmental Science & Technology, Vol. 47, No. 2, 2013,
pp. 906-913.
[14] S. Batterman, J. Y. Chin, C. Jia, C. Godwin, E. Parker, T.
Robins, P. Max and T. Lewis, “Sources, Concentrations,
and Risks of Naphthalene in Indoor and Outdoor Air,”
Indoor Air, Vol. 22, No. 4, 2012, pp. 266-278.
[15] T. E. McHugh, J. A. Connor and F. Ahmad, “An Empiri-
cal Analysis of the Groundwater-to-Indoor-Air Exposure
Pathway: The Role of Background Concentrations in In-
door Air,” Environmental Forensics, Vol. 5, No. 1, 2004,
pp. 33-44. http://dx.doi.org/10.1080/15275920490424024
[16] M. Vidali, “Bioremediation. An Overview,” Pure and
Applied Chemistry, Vol. 73, No. 7, 2001, pp. 1163-1172.
http://dx.doi.org/10.1351/pac200173071163
[17] International Agency for Research on Cancer, “Tradi-
tional Herbal Medicines, Some Mycotoxins, Naphthalene,
and Styrene,” IARC Monographs on the Evaluation of
Carcinogenic Risks to Humans, Vol. 82, IARC, Lyon,
2002.
[18] United States Environmental Protection Agency, “Inte-
grated Risk Information System (IRIS) Toxicological Pro-
file 0436,” Naphthalene, 1998.
[19] G. Garvey, R. DeHate, E. A. Kazmarek and C. Geiger,
“Implications of Naphthalene Carcinogenicity for MGP
Investigation and Cleanup,” Electric Power Research In-
stitute, Atlanta, 2007.
[20] Agency for Toxic Substances and Disease Registry,
“Toxicological Profile for Naphthalene 1-Methylnaphtha-
lene, and 2-Methylnaphthalene,” U.S. Department of Health
and Human Services, Public Health Service, Atlanta,
2005.
[21] United States Environmental Protection Agency, “Build-
ing Assessment and Survey Evaluation (BASE 1994-
Open Access JEP

Assessment of Public Health Risks Associated with Naphthalene Entering Residences and
Commercial Space from Vapor Intrusion at MGP Sites
Open Access JEP
17
1996),” 2001.
[22] P. S. Price and M. A. Jayjock, “Available Data on Naph-
thalene Exposures: Strengths and Limitations,” Regula-
tory Toxicology and Pharmacology, Vol. 51, No. 2, 2008,
pp. 15-21. http://dx.doi.org/10.1016/j.yrtph.2007.10.010
[23] National Toxicology Program, “Toxicology and Carcino-
genesis Study of Naphthalene in B6C3F1 Mice (Inhala-
tion Studies),” Technical Report Series No. 410, 1992.
[24] National Toxicology Program, “Toxicology and Carci-
nogenesis Study of Naphthalene in F344/N Rats (Inhala-
tion Studies),” Technical Report Series No. 500, 2000.
[25] J. R. Lewis, “Naphthalene Animal Carcinogenicity and
Human Relevancy: Overview of Industries with Naph-
thalene-Containing Streams,” Regulatory Toxicology and
Pharmacology, Vol. 62, No. 1, 2012, pp. 131-137.
http://dx.doi.org/10.1016/j.yrtph.2011.12.004