PUBLIC HEALTH ASSESSMENT
VOLUNTEER ARMY AMMUNITION PLANT
CHATTANOOGA, HAMILTON COUNTY, TENNESSEE
FACILITY NO. TN6210020933
September 7, 2004
Figure 1: Area Map
Figure 2: Volunteer Army Ammunition Plant (VAAP) Sites
Figure 3: ATSDR's Exposure Evaluation Program
Figure 4: Drainage Basins
Figure 5: Demographics Map
- The Army Corps of Engineers (ACOE) built the original facilities to support World War II (WW II). Initial operation began in July 1942 with the Hercules Powder Company of Wilmington Delaware as the operating contractor. Sixteen TNT batch process lines and associated nitric and sulfuric acid facilities operated until August 1945. Approximately 823 million pounds (lbs) of TNT were produced for WWII at VAAP (IT Corp 1994).
- From January 1946 to the spring of 1952, VAAP was officially on standby status and operated and maintained by the government (USATHAMA 1978; Army 2003).
- VAAP was reactivated in 1952 for the Korean War, and operated by the Atlas Chemical Industries of Wilmington Delaware until 1957. Approximately 283 million lbs of TNT were produced for the Korean War (IT Corp 1994). During this period the first Army studies were undertaken to examine methods of pollution control but VAAP was put on standby status before pollution strategies could be implemented (IT Corp 1994).
- VAAP was on standby status from 1957 until 1965 when it was reactivated for the Vietnam War (Army 2003a; IT Corp 1994). Between the Korean and Vietnam Wars there was considerable residential development north of VAAP and adjacent to the Chickamauga Lake (IT Corp 1994). From March 1957 to December 1964 the plant was under the protective surveillance of Atlas Chemical Industries; and in December 1964 until September 1965 protective surveillance was passed onto Farmers Chemical Association Inc. (subsequently known as CF Industries, Incorporated [CFI]). In September 1965 a new contract with Atlas was entered into with the Army (SI 1994). On January 6, 1972, Atlas merged into ICI America Incorporated (ICIA), and is currently called ICI Americas, Inc. (Army 2003a; USATHAMA 1978).
- In 1961, the government leased the "CFI Lease Area," an area along the western border of VAAP, to CFI (Bonds 1985). Previously the area had been used for nitric and sulfuric acid production (Army 2003a). In 1962, CFI used the existing acid facilities and built an ammonia plant on the 824-acre lease area to produce ammonium nitrate fertilizer, urea, and related products (Army 2003a). In 1963 a urea plant was put into operation, thereby doubling CFI's production capacity (IT Corp 1994).
- In 1965, VAAP was reactivated and ten TNT batch process lines were used to produce TNT for the Vietnam War (IT Corp 1994).
- Additionally, upon reactivation, the Army decreased the number of acres in the original CFI lease area and took over the operation of some of the acid production equipment to increase nitric acid production and sulfuric acid concentration capacity. Therefore, in 1966, CFI constructed a new acid plant adjacent to the ammonia plant, and operated the existing acid plant in the lease area for the Army (Bonds 1985; Army 2003a).
- In February1969, as VAAP began to upgrade facilities, the batch processing lines began to decrease (Report 123, 1978; Army 2003a). From July 1971 to 1975, six new CIL continuous process lines were built in an area where four old batch process lines were previously razed (Army 2003a). Lines 1, 2, and 3 were modernized by May 1974, and a contract for modernizing Lines 4, 5, and 6 was awarded in June 1974. However, from November 1974 to March 1977, only one of the six Canadian Industries Limited (CIL) lines was operated because plant operations ceased before the other five became operational (IT Corp 1994; USATHAMA 1978).
- In June 1970, the Army began to build the New Acid Area. The area included a Direct Strong Nitric (DSN) Acid Facility, an Ammonia Oxidation Process (AOP) Nitric Acid Facility, and Sulfuric Acid Regeneration (SAR) Facilities (used for oleum production) (IT Corp 1994; USATHAMA 1978).
- In 1972, a carbon dioxide plant was constructed at the CFI Lease Area and an industrial waste water system was built to treat and recycle ammonium nitrate wastewater (IT Corp 1994; USATHAMA 1978).
- By January 1975, all batch process lines stopped and, in 1977, TNT production at VAAP ceased altogether and the plant was placed on inactive status (Army 2003a). A total of 1,765 million lbs of TNT were produced for the Vietnam War (IT Corp 1994).
- CFI produced commercial ammonium nitrate at the CFI Lease Area until 1982. From 1982 to 1985 the CFI Lease Area was inactive, and the CFI facilities were ultimately dismantled for salvage between 1985 and 1986 (IT Corp 1994). The Army acid facilities in the southern area were dismantled during the 1950's and 1960's. The northern acid facilities were dismantled by approximately 1997 (Army 2003a, IT Corp 1995, Public Comment 2004b).
- During the 1990s, VAAP operated the burning ground to treat materials contaminated with TNT or TNT waste materials generated while VAAP was operational (EPA 2003a; IT Corp 1994, Public Comment 2004b)
- On September 5, 1995, approximately $5 million was awarded to ICIA to reactivate and modify one of the TNT lines at VAAP for production of commercial TNT. The contract was awarded under the Armament Retooling and Manufacturing Support Act of 1992, and the work was to be complete by July 31, 1996 (DOD 1995). This work was never completed and the ICIA contract expired on December 31, 1998. Tecumseh Professional Associates became the new contracting operator, however, the project remained and remains inactive (Army 2003a).
TNT production involves the chemical nitration (adding a nitrogen dioxide [NO2] group to an organic compound) of toluene (C7H8) to create TNT (C7H5N3O6). Nitric acid (HNO3) is used as the source of nitrogen dioxide for each of the three nitration steps required. Sulfuric acid (H2SO4) is used to absorb water formed during the nitrogen reactions. Maintaining the correct nitric acid concentration in the reactors is essential to successful nitration, and sulfuric acid does this by acting as dehydrator. The addition of nitrogen dioxide groups to toluene becomes increasingly difficult as more nitrogen dioxide groups become attached. In fact, for the third group to attach, strong nitric acid (98 percent), oleum (108 percent, concentrated sulfuric acid to which sulfur trioxide [SO3] is added), and increased temperatures are needed (USAEHA 1985).
The following information briefly describes the TNT manufacturing processes used at VAAP and identifies the types of chemical by-products that could be expected from the production process. Two TNT manufacturing methods, both located in VAAP-32-TNT Manufacturing Valley, were used: the batch process was used in 16 lines and the Canadian Industries Limited (CIL) process was used in continuous process lines. The chemical nitration of toluene to create TNT is the same for both processes.
In addition, nitric acids, sulfuric acids, and oleum were also produced at VAAP to support TNT production. These production processes are also briefly described to identify the types of potential chemical by-products expected. This information is based primarily on material provided by VAAP, and the US Environmental Protection Agency (EPA) AP-42 (Chapter 6.3, Explosives; Chapter 8.8, Nitric Acid; and Chapter 8.10, Sulfuric Acid).
Combining nitric acid with toluene in the presence of sulfuric acid ultimately forms TNT and water containing sulfuric acid. The sulfuric acid is not consumed in the process. Figure B-1 schematically shows the production process and the compounds emitted to the air or present in the waste products (EPA 1983).
After the nitration process is complete, the crude TNT is washed to remove the remaining acid. The acidic rinsate containing sulfuric acid with un-reacted nitric acid and TNT production products (yellow water) may be recycled back into the nitration process. The washed TNT is neutralized with soda ash (sodium carbonate [Na2CO3]) and purified with Sellite (a water based mixture of sodium sulfite [Na2O3S] and sodium hydrogen sulfite [HNaO3S]) to remove impurities. Effective removal is a function of pH, temperature and Sellite concentration. Soda ash and sulfur dioxide (SO2) are added to the Sellite mixture to maintain an optimum pH range. Anecdotal information indicates that at VAAP, the purified TNT was washed with hot water, melted, dried, and either flaked (Public Comment 2004b).
TNT Production By-Products
The following table identifies the by-product categories resulting from TNT production.
|Table B-1: By-Products from TNT Production|
|Aqueous By-Products||Gaseous By-Products||Solid By-Products|
|Waste sulfuric acid |
Waste nitric acid
|Nitrogen oxides (NO and NO2) |
Sulfur oxides (SO2 and SO3)
Nitric acid mist
Sulfuric acid mist
|No solid by products were identified in the literature review.|
|* Each of these solutions is likely to contain various combinations of sulfuric acid, nitric acid and TNT production products (isomers of TNT, DNT and nitro-toluene)|
Liquid waste streams primarily consisted of redwater, pink water, and waste acids generated during the TNT nitration or purification processes. Yellow water is generated during the nitration process and is highly acidic. The used Sellite solution is named 'redwater' because it reacts with sunlight and turns a deep red color. Redwater is generated from the purification process. The water used to clean TNT contaminated areas generally turns a pink color, and is therefore called 'pink water'. While these solutions contained various combinations of acidic compounds, TNT isomers, isomers of dintritrotoluene (DNT) and other chemical compounds; each solution is chemically different than the others (EPA 1983; USAEHA 1985, Public Comment 2004b).
Direct discharge as a liquid waste, collection and resale, and concentration and incineration are three options for disposing of the redwater (EPA 1983). Some portion of the VAAP redwater was incinerated; the ash from the incineration process, identified as 'redwater ash,' was buried onsite. Records also indicate that the yellow and pink waters, after settling, were combined with wastewater and neutralized. These wastes were then added to the redwater at the redwater treatment plant. The redwater was then evaporated to 35% solids and sold to the paper industry (USAEHA 1985).
Redwater treatment facilities were located at considerable distances, at times over 1 mile, from the TNT production lines for safety reasons (USAEHA 1985). Anecdotal information indicates that initially, when TNT was produced using the batch process, the redwater was transported in open top flumes to the redwater treatment facility. After the continuous TNT production lines were constructed, the redwater was transported in a 'pipeline' system. Transport lines were steam-traced (warmed by steam) to prevent the redwater from solidifying within the line (Public Comment 2004).
The primary air emissions from the TNT nitrification process were nitrogen oxides (NOx; primarily nitrogen oxide and nitrogen dioxide) and sulfur oxides (SOx; primarily sulfur dioxide and sulfur trioxide). Nitric acid mist and sulfuric acid mist were also emitted during some of the production steps. For all of these compounds, the actual amount emitted varies greatly; partly due to the kind of production process used (batch vs. continuous) and the quality of air pollution control equipment used (EPA 1983).
The acids necessary for the TNT nitration process were produced in VAAP-1-East Acid Area (constructed in the early 1940s and operated until 1970), VAAP-33-New Acid Area (constructed in the early 1970s), and the CFI lease area (Public Comment 2004). The main products of this area were: nitric acid, sulfuric acid, oleum, and a mixture of strong nitric acid and oleum. However, it is possible that much of the oleum was produced off-base during the late 1960's (Chattanooga Times, April 18, 1969).
Documents reviewed by ATSDR suggest that VAAP may have used the direct strong nitric (DSR) process to produce nitric acid. This entails first burning ammonia to form nitric oxide (NO) and steam. The nitric oxide is then condensed and converted with strong nitric acid to nitrogen dioxide, which subsequently forms dinitrogen tetraoxide (N2O4). The oxidation of dinitrogen tetraoxide results in 100% nitric acid (USAEHA 1985). Anecdotal information indicates VAAP actually used the ammonia oxidation process (AOP) during most of the TNT production years and only used the DSR process during the late 1970's. The AOP process only produces 60% nitric acid by absorbing the nitrogen oxides in water or weak nitric acid (Public Comment 2004b).
Concentrated sulfuric acid production starts with molten elemental sulfur, which is burned in clean air to produce sulfur dioxide. The gaseous sulfur dioxide is passed over a vanadium pentoxide catalyst to produce sulfur trioxide. The sulfur trioxide gas enters the bottom of an absorption tower and migrates up through a downward flowing solution of sulfuric acid and water. The water combines with the sulfur trioxide to produce more sulfuric acid. The solution at the bottom of the tower is concentrated sulfuric acid (EPA 1998b; USAEHA 1985, Public Comment 2004b).
Oleum is a mixture of concentrated sulfuric acid with dissolved sulfur trioxide. The VAAP sulfuric acid regeneration (SAR) plant produced oleum by a process similar to that used for sulfuric acid. However, the sulfur trioxide was sent to an absorption tower where it flowed through a solution of concentrated sulfuric acid. In this case the resulting solution (oleum) consists essentially of only sulfuric acid and sulfur trioxide (EPA 1998b, USAEHA 1985). The oleum was used to produce mixed acid and in the nitration process.
Mixed acid was produced by combining strong nitric acid with oleum; the final product was approximately one-half strong nitric acid and one-half sulfuric acid.
Acid Production By-Products
The following table identifies the by-product categories resulting from acid production.
|Table B-2: By-Products from Acid Production|
|Aqueous By-Products||Gaseous By-Products||Solid By-Products|
|Nitric Acid |
|Nitrogen oxide (NO) |
Nitrogen dioxide (NO2)
Sulfur dioxide (SO2)
Nitric acid mist
Sulfuric acid mist
The primary emissions from nitric acid production are nitrogen oxide and nitrogen dioxide, which are the visible emissions. Nitric acid mist emissions from properly operating plants are minimal and were not quantified in EPA AP-42. Nitrogen oxide and nitrogen dioxide emissions occur during production and storage. The actual emissions are highly variable and depend on the type of pollution control technology used (EPA 1998a, EPA 2003c).
Small quantities of hydrogen sulfide and sulfur dioxide (approximately 1% or less each) are present in molten sulfur (Montana Sulphur 1977). Small amounts of hydrogen sulfide gas may be liberated from the molten sulfur. In an open environment the hydrogen sulfide concentration will be extremely low-below levels of health concern. Typically hydrogen sulfide concentrations in air are only a concern when the molten sulfur is stored in an enclosed space; allowing the hydrogen sulfide to accumulate (Amerada Hess 2000). Based on this information ATSDR concluded that hydrogen sulfide gas concentrations in open air, outside of the occupational environment, would be below levels of health concern for the general public and were not considered further.
Sulfur dioxide and sulfuric acid mist are the primary sulfur compounds released to the air during production of oleum and sulfuric acid. Sulfur trioxide is also formed and released during the production process; however in the environment, sulfur trioxide rapidly reacts with the water vapor to form sulfuric acid (ATSDR 1998).
Acid sewer lines routed waste from the production and storage areas in VAAP-1-East Acid Area to the Neutralization Plant. Wastes from VAAP-33-New Acid Area were routed to a diverter station located adjacent to Pond 10 before being discharged for eventual release to Waconda Bay to the north via the Surface Water Discharge Area (IT Corp 1994).