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1. ATSDR > Public Health Assessments & Consultations

PUBLIC HEALTH ASSESSMENT

U.S. AIR FORCE PLANT NO. 4 (GENERAL DYNAMICS)
FORT WORTH, TARRANT COUNTY, TEXAS

FIGURES

Figure 1 - U.S. Air Force Plant 4 Site Location

Figure 2 - Identified Potential Areas of Concern

Figure 3 - USAF Plant 4-- ½ Mile Radius Demographics

Figure 4 - USAF Plant 4-- Demographic Statistics Within One Mile of Site

Figure 5 - Flow Direction in the Regional Paluxy Aquifer

Figure 6 - Estimated Boundaries of TCE Plume in Alluvial Groundwater (Terrace Alluvial Aquifer)

Figure 7 - Estimated Boundaries of TCE Concentrations in the Paluxy Upper Sand (East Paluxy Plume)

Figure 8 - Estimated Boundaries of TCE in the Regional Paluxy Aquifer (West Paluxy Plume)

APPENDICES

Appendix A Table 1
Number of Observed and Expected Deaths and Race Adjusted Standardized Mortality Ratios for Eight Types of Cancer for White Settlement for the Period 1986 to 1995

*The SMR (standardized mortality ratio) is defined as the number of observed deaths divided by the number of expected deaths. The latter are based on race-, sex-, and age-specific cancer mortality rates for Texas during the period 1986-1995.

**To determine if the SMR was significantly different from one (1.00), we calculated a 95% confidence interval for each type of cancer. The 95% confidence interval indicates the range in which we would expect the SMR to fall 95% of the time. If the confidence interval includes one (1.00), the observed to expected are not statistically significant; the SMR is within the range that would be expected based on the mortality experienced by the entire state.

Prepared by: Cancer Registry Division, Texas Department of Health 7/10/97

Appendix B - Acronyms and Abbreviations

AFP4	Air Force Plant 4 (Formerly General Dynamics)
ATSDR	Agency for Toxic Substances and Disease Registry
CERCLA	Comprehensive Environmental Response, Compensation and Liability Act of 1990
CI	Confidence Interval
CoPCs	Contamints of Potential Concern
CREG	Carcinogenic Risk Evaluation Guide
DCE	Dichloroethylene
DOD	Department of Defense
DOE	Department of Energy
EMEG	Environmental Media Evaluation Guide
EPA	U.S. Environmental Protection Agency
ESL	Effects Screening Level - Screening levels established by the TNRCC
FDA	Food and Drug Administration
HAC	Health Assessment Comparison Value
HOD	Health Outcome Data
IRP	Installation Restoration Program
LTHA	Lifetime Health Advisory
MCL	Maximum Contaminant Level
MCLG	Maximum Contaminant Level Goal
mg/kg	Milligrams per Kilogram
mg/L	Milligrams per Liter
MRL	Minimal Risk Level
na	None available
NAS	Naval Air Station (Formerly Carswell Air Force Base)
NARF	Nuclear Aerospace Research Facility
NPL	National Priorities List
PA/SI	Preliminary Assessment/Site Inspection
PAHs	Polycyclic Aromatic Hydrocarbons
PCBs	Polychlorinated Biphenyls
PHA	Public Health Assessment
PMCLG	Proposed Maximum Contaminant Level Goal
ppbv	parts per billion volume
QA/QC	Quality Assurance/Quality Control
RfD	Reference Dose
RI/FS	Remedial Investigation/Feasibility Study
RMEGs	Reference Dose Based Media Evaluation Guides
ROD	Record of Decision
SARA	1986 Superfund Amendments and Reauthorization Act
VOC's	Volatile Organic Compounds (example - Benzene)
Semi-VOCs	Semi-Volatile Organic Compounds (example - Polycyclic Aromatic Hydrocarbons)
SMR	Standardized Mortality/Morbidity Ratio
TCE	Trichloroethylene
TDH	Texas Department of Health
TNRCC	Texas Natural Resource Conservation Commission
TPH	Total Petroleum Hydrocarbons
USGS	United States Geological Service
µg/L	Micrograms per Liter
VOCs	Volatile Organic Compounds

Appendix C - Definitions

Aqueduct	A conduit for water
Aquifer	A layer of permeable rock containing water
Aquitard	Impenetrable barrier between aquifers
Background	Concentrations detected in an area that cannot be attributed to the site
Bioaccumulate	To build up in the tissue of an animal, human, or plant
Caustic	Corrosive
Contaminant	An undesirable element that causes impurity or pollution
Dermal	Of or relating to the skin
Expected	An epidemiologic term referring to the number of cases that we would expect to find in a specific population based on the number that we see in a reference population
Facility	Something built to perform a specific function
Groundwater	Water beneath the ground surface
Indeterminate	Uncertain, undecided
Infiltrate	To cause to permeate something by penetrating its pores or interstices
Ingest	To take in, to eat
Lipophilic	Having an affinity for lipid (fat)
Migrate	To move from one place to another
Observed	An epidemiologic term referring to the actual number of cases found in a specific population
Plume	An elongated, mobile area of contaminated media; usually beginning at a contamination source and indicating the spread of contamination
Seepage	A quantity of fluid that has oozed slowly from the ground to the surface
Seine	Type of net used to catch fish
Site	A place or spatial location of an actual or planned structure or set of structures
Terrace Alluvial	A stream deposit of unconsolidated sediments produced when a stream downcuts a flood plain or valley floor
Topographic high	An area that is higher than other nearby areas
Transect	To cut across at a right angle

Appendix D - Summary of No Further Action Sites at Air Force Plant 4

Site Description	Evaluation	Comments
Landfill No. 1 A six-acre site that was used from 1942 to approx. 1966 for disposal of general refuse,	The area was closed in 1966 and paved for employee parking. During the RI, TCE (nd to 0.11 mg/kg) and toluene (nd to 350 mg/kg) were detected. Benzo(a)pyrene was detected (1.1 to 62 mg/kg) below the asphalt cover and was attributed to the asphalt.	On the basis of the baseline risk assessment and because the benzo(a)pyrene appears to be derived from the overlying asphalt, the soil at this location does not pose an unacceptable risk to humans. The selected remedy for this location is no action.
Landfill No. 2 An eight-acre site used from the early 1940s to early 1960s for the disposal of construction rubble, plaster, lumber, and tires.	There were no indications that hazardous materials were disposed at this location. The area is now grass covered. In 1989, toluene was detected in one of 39 samples at a concentration of <1.0 mg/kg.	On the basis of these analytical results, the soil at this location does not pose an unacceptable risk to human health or the environment. The selected remedy for this location is no action.
Fire Training Area No. 2 A 50-ft diameter earthen ring located north of Landfill No. 1.	This area was used for semiannual fire-training exercises between 1955 and 1965. It is currently overlain with asphalt from the West Parking Lot. TCE and 1,2-DCE were detected at concentrations < 1.0 mg/kg.	On the basis of the baseline risk assessment, the soil at this location does not pose an unacceptable risk to human health or the environment. The selected remedy for this location is no action.
Fire Training Area No. 3 Located near the western edge of AFP4 and northeast of Landfill No. 4	This area was used for fire-training exercises in the 1960's. It is currently grass covered. The exact location of this site could not be determined. Laboratory analysis of groundwater samples indicate no elevated concentrations of site contaminants.	On the basis of available information, the selected remedy for this location is no action.
Fire Training Area No. 4 Reported to be at the northern tip of AFP4.	Fire department personnel report that no firefighting exercises were ever conducted in this area, The exact location could not be determined but personnel reported that the site received clean-fill from a foundation excavation.	On the basis of available information, the selected remedy for this location is no action.
Fire Training Area No. 5 A 35 ft-by-45 ft shallow pit located at the south-central boundary of AFP4.	It was used for fire training exercises in the mid 1960's. Low concentrations of VOCs and Semi-VOCs (<2.0 mg/kg) were detected in soil boring samples.	On the basis of the baseline risk assessment, the soil at this location does not pose an unacceptable risk to human health or the environment. The selected remedy for this location is no action.
Fire Training Area No. 6 A 50-square foot gravel lined area approximately 2 feet deep, surrounded by an earthen berm.	This area was the primary fire department training area from the late 1960s to 1982. Interim remedial action was performed at this site to remove oil/fuel contaminated soil. Subsequent soil sampling has detected low concentrations of VOCs and Semi-VOCs (generally less than 1.0 mg/kg; two Semi-VOCs were detected at 3.0 mg/kg).	On the basis of the baseline risk assessment, the soil at this location does not pose an unacceptable risk to human health or the environment. The selected remedy for this location is no action.
Chrome Pit No. 1 An unlined earthen pit that received liquid wastes during the early 1940s.	Building 181 was constructed on this site. Analytical results indicate the presence of chromium in the soils around Building 181; however, the concentrations are below the upper background limit for the Western United States.	Given the limited usage of the pit and its presence beneath a building, the selected remedy for this area is not action.
Chrome Pit No. 2 An unlined earthen pit located near the southwest corner of the Assembly Building/ Parts Plant	This pit reportedly received liquid chrome wastes during the mid-1940s; however, the actual location could not be determined.	Since this site could not be located, the selected remedy for this area was no action.
Chrome Pit No. 3 A large earthen pit (55 ft wide x 165 ft long x 15 ft deep) located in the southern portion of AFP4 west of Building 12.	It was operational from 1957 to 1973 and received chrome sludge, dilute metal solutions, and other unidentified liquids. An interim action was conducted in Dec. 1983 and Jan. 1984 to excavate and remove approximately 8,900 cubic yards of soil. Following the excavation and removal, soil sampling detected the presence of TCE in one sample at a concentration of 4.8 mg/kg.	On the basis of the low concentrations of organic compounds detected following the removal of the soil, this location does not pose an excess risk to human health or the environment. The selected remedy for this area is no action.
Die Yard Chemical Pits Three pits (approximately 20 ft wide x 90 ft long x 10 ft deep) located in the southern portion of AFP4.	In 1962, this area was graded and the entire area was paved for parking. In 1983 and 1984, they excavated the original die pits, and 1,100 cubic yards of contaminated soil were removed. Post excavation confirmatory sampling detected VOCs at concentrations between non-detect and 5.6 mg/kg. Subsequent sampling has detected VOCs at concentrations less than 0.5 mg/kg.	On the basis of these data, the soil in this area does not pose an excess risk to human health and the environment. The selected remedy for this area is no action.
Fuel Saturation Area No. 1 Soil located immediately west of the Assembly Building/Parts Plant, partially beneath Building 14.	Soil at this location reportedly became saturated with JP-4 leaking from underground piping during the 1970s and early 1980s. Ethylbenzene and benzene were detected in three of 45 samples at concentrations less than 1.0 mg/kg. One sample contained Semi-VOCs (less than 2.7 mg/kg).	The baseline risk assessment determined that the soil contamination at this site does not cause an excess risk to human health and the environment. The selected remedy for this area is no action.
Fuel Saturation Area No. 2 Soil surrounding an underground pipeline in the northwest portion of AFP4.	Originally reported as a potential site because of reports of saturated soil along an underground pipeline in the northwest portion of AFP4. No contaminants of concern were detected in soil from this area.	On the basis that no contaminants pose a risk to human health or the environment, the selected remedy for this area is no action.
Fuel Saturation Area No. 3	Investigated because of reports of leaking underground fuel lines in the area. Acetone, benzene, and ethylbenzene were detected at concentrations below 1.0 mg/kg. Semi-VOCs were detected at concentrations between 0.85 and 5.9 mg/kg.	The baseline risk assessment determined that the soil contamination at this site does not cause an excess risk to human health and the environment. The selected remedy for this area is no action.
Former Fuel Storage Area The site of a former above- ground 1.000,000-gallon JP-4 fuel storage tank located in the southwest portion of AFP4.	The tank was used from the early 1940s to 1962 when it was removed from the site and relocated. Soil beneath the tank reportedly contained jet fuel at the time the tank was removed. In 1991, soil samples were collected from four borings that were drilled around a monitoring well installed at the site. No VOCs, semi-VOCs, or other contaminants of concern were identified in those samples.	On the basis of no contaminants that pose a risk to human health or the environment, the selected remedy for this area is no action.
Solvent Lines This area is located in the north-central portion of AFP4.	The lines were used to transport xylene, 2-butanone, and kerosene from 1942 until 1944. This area was identified as requiring investigation on the basis of personnel accounts of reported leaks. In 1985, two soil samples collected during installation of a monitoring well were analyzed for xylene and 2-butanone; neither compound was detected. VOCs in groundwater samples did not exceed their respective MCLs.	This area was designated as No Further Action by the Plant 4 Technical Review Committee before the start of the remedial investigation.
Nuclear Aerospace Research Facility Approximately 120 acres located on at the northern tip of AFP4.	This area was the site of three atomic reactors used between 1953 and 1974 for research and development activities In 1974, this facility was decontaminated and dismantled. High-level and low-level radioactive components were segregated and shipped to regulated off-site disposal areas. In 1989, alpha radiation in soil samples ranged from 6.7 to 12.4 picocuries per gram (pCi/g). Beta radiation ranged from 10.0 to 23.1 pCi/g. Gamma radiation was not measured directly but samples were analyzed for cesium-137, which was not detected. The alpha and beta activities were deemed typical of normal background levels encountered in undisturbed soil. In 1991, six sediments samples were collected from Lake Worth near the NARF facility site. These samples were tested for cesium-137, radium-226, thorium-230, and uranium. The concentrations measured were deemed typical of normal background levels encountered in most undisturbed soil.	On the basis of these data, the NARF site does not pose a risk to human health or the environment. The selected remedy for this area is no further action.
West Compass Rose A 150-square foot area located in the northern portion of AFP4.	This area was included as a possible site on the basis of personnel recollections of past surface spills. In 1985, 24 shallow borings were drilled in the area. Organic vapors were detected in samples from 3 of the 24 borings. One sample was submitted for VOC analyses, but no contaminants were detected. In 1991, an additional boring was drilled and no fuel hydrocarbons were present in the soil samples from this boring.	On the basis of these data, the West Compass Rose site does not pose a risk to human health or the environment. The selected remedy for this area is no further action.
Jet Engine Test Stand Located in the northern portion of AFP4.	This area was included as a possible area of concern on the basis of employee reports of jet fuel and gasoline in a sump near the site. In 1986, 2 of 5 samples contain fuel hydrocarbons at concentrations of 1,700 and 1,300 mg/kg. In 1991, 2 of 7 samples contained low concentrations (between 1.1 and 5.1 mg/kg) of semi-VOCs.	On the basis of these data, it was determined that this area does not pose an excess risk to human health or the environment and the selected remedy for the area is no action.
Underground Storage Tanks No. 19 and No. 20 Two 12,000-gallon-capacity tanks formerly located in the south-central portion of AFP4.	No. 19 was used to store 2-butanone; No. 20 was used to store 2-butanone, ethylbenzene, and xylene. Both tanks were removed in 1988 and the area beneath the tanks was excavated. In 1991, 27 soil samples were collected. Concentrations of less than 1.0 mg/kg. were detected for 2-butanone, xylene, and ethylbenzene.	On the basis of the analytical data, these areas do not pose an excess risk to humans or the environment. The selected remedy is no action
Underground Storage Tanks No. 24A and 24B Two 8,000-gallon tanks located side-by-side in the south-central portion of AFP4.	These tanks were excavated and removed in 1988. Low concentrations of organics (<1.0 mg/kg) were detected in confirmatory soil samples. In 1991, nine soil samples were collected and no organic contaminants of concern were detected in any of these samples.	On the basis of the analytical data, these areas do not pose an excess risk to humans or the environment. The selected remedy is no action
Underground Storage Tank No 25A Located adjacent to the Jet Engine Test Stand in the northern portion of AFP4.	This area formerly contained two vertical underground tanks used to store JP-4. The tanks were removed in 1988. In 1991, eleven soil samples were submitted for analysis; ethylbenzene was detected at concentrations less than 1.0 mg/kg and 2-methylnaphthalene was detected at 3.9 mg/kg.	On the basis of the analytical data, these areas do not pose an excess risk to humans or the environment. The selected remedy is no action
Underground Storage Tank No. 30 A 2,000-gallon steel tank, formerly located in the northern portion of AFP4.	This tank was used to store JP-4. The tank was installed in 1956 and removed in 1988. In 1991, eight samples were collected from this area; no VOCs or semi-VOCs were detected in these samples.	On the basis of the analytical data, these areas do not pose an excess risk to humans or the environment. The selected remedy is no action

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