Areas of concern are those sites at which field observations indicate a possibility that waste disposal activities may have taken place. AOCs at CSSA have been identified through geophysical surveys, soil gas surveys, or observation of waste materials on the ground surface. Since there are no records at CSSA that waste activities did indeed take place in these areas, they are called AOCs. On this basis, all of the AOCs are considered to be low priority sites. A description of each AOC is provided in the following paragraphs.
AOC-35 is located on the border between the outer and inner cantonment surrounding well 16 and has an area of approximately 0.1 acre. In 1995, the site was included in the seven potential source areas around well 16 for which EM and GPR geophysical surveys were performed. In a follow-up field effort, the area of the geophysical survey was increased to ½-mile radius around well 16; no anomalies were identified at this site during the focused geophysical survey. Twenty-one soil gas survey samples were collected and analyzed for chlorinated and aromatic volatile organics; PCE was the only target analyte detected. During an installation-wide surface geologic mapping effort, two distinct fault zones, including one near well 16 were mapped. Specific data regarding all site activities may be found in AOC 35 links.
Future plans at the site include completing a record search, field locating and mapping the site, and collection of surface soil samples. This work is tentatively planned, but it is not currently included in any delivery order. If the site is found to meet RRS1 criteria after this work has been completed, a closure report will be prepared in accordance with TNRCC closure requirements.
AOC-36 is located in the northern portion of the inner cantonment, and has an area of approximately 0.6 acres. Up to six 155-millimeter shells containing mustard gas were potentially buried and detonated at this site in 1942. In 1958, the U.S. Army Chemical Corps Technical Escort Unit assisted CSSA in detection and disposal of any remaining shells. Decontamination of possible residual mustard was conducted using calcium hypochlorite. A certificate stating that all 155-mm mustard filled rounds and resultant scrap metal buried in 1942 were recovered, destroyed, and decontaminated was signed by the Technical Escort Unit head. In 1993, 1957 and 1962 aerial photographs were reviewed to identify mustard gas burial locations. In 1995, EM geophysical surveys were performed, during which no anomalies were found. Also, 29 soil-gas survey samples were collected and analyzed for chlorinated and aromatic volatile organics; PCE, TCE and DCE were detected. Late in the year, an additional ten soil-gas survey samples were collected; previously identified constituents as well as carbon tetrachloride were detected. In 1997, a portion of the site identified as a mustard gas burial site was identified and surveyed. Interviews of two former CSSA personnel were conducted, in which burial site locations were confirmed. In February 1997, following these interviews, a magnetometer sweep was completed of the surveyed areas and the areas identified by the former CSSA personnel. Metal items determined to be free of explosives were placed in roll-off containers for recycling. UXO items were segregated for later disposal. In 1997, areas with noted anomalies were excavated and sifted to determine if the anomaly was due to buried UXO or mustard gas shells. No mustard gas shells or evidence of mustard gas shells were identified throughout the site. At the conclusion of investigative work, a final report summarizing findings was submitted. The final report was sent to TNRCC in March 1999 for their concurrence for site closure. TNRCC approved the site for closure in July 1999. Specific data regarding all site activities may be found in AOC 36 links.
AOC-37 is located in the southern portion of the north pasture, and has an area of approximately 0.4 acre. A geophysical survey was conducted at the site in 1995, during which no geophysical anomalies were identified. Specific data regarding all site activities may be found in AOC-37 links.
Since no anomalies were found, it is anticipated that the site will be closed under RRS1. This work is tentatively planned, but it is not currently included in any delivery order.
AOC-38 is located in the northern portion of the inner cantonment, and has an area of approximately 35 acres. A geophysical survey was conducted at the site in 1995, during which one geophysical anomaly, as well as a 1.5 inch diameter pipe, was identified. Twenty-six soil-gas survey samples were collected and analyzed for chlorinated and aromatic volatile organics; PCE and TCE were detected. Late in the year, an additional 94 soil-gas samples were collected. Specific data regarding all site activities may be found in AOC-38 links.
Future plans at the site include completing a record search, field locating and mapping the site, drilling and sampling of soil borings, and collection of surface soil samples. This work is tentatively planned, but it is not currently included in any delivery order. If the site is found to meet RRS1 criteria after this work has been completed, a closure report will be prepared in accordance with TNRCC closure requirements.
AOC-39 is located on the border between the outer and inner cantonment, to the west of well 16, and has an area of approximately ½ acre. A geophysical survey was conducted at the site in 1995, during which two geophysical anomalies were identified. Also, nine soil-gas survey samples were collected and analyzed for chlorinated and aromatic volatile organics; PCE was the only target analyte detected. Specific data regarding all site activities may be found in AOC-39 links.
Future plans at the site include completing a record search, field locating and mapping the site, drilling and sampling of six soil borings, and collection of six grab surface soil samples. This work is tentatively planned, but it is not currently included in any delivery order. If the site is found to meet RRS1 criteria after this work has been completed, a closure report will be prepared in accordance with TNRCC closure requirements.
AOC-40 is located on the border between the outer and inner cantonment, to the east of well 16, and has an area of approximately ½ acre. A geophysical survey was conducted at the site in 1995, during which one geophysical anomaly that may be caused by an overhead power line or subsurface disturbance was identified. Also, nine soil-gas survey samples were collected and analyzed for chlorinated and aromatic volatile organics; PCE was the only target analyte detected. Specific data regarding all site activities may be found in AOC-40 links.
Future plans at the site include completing a record search, field locating and mapping the site, drilling and sampling of soil borings, and collection of surface soil samples. This work is tentatively planned, but it is not currently included in any delivery order. If the site is found to meet RRS1 criteria after this work has been completed, a closure report will be prepared in accordance with TNRCC closure requirements.
AOC-41 is located in the southern portion of the north pasture, and has an area of approximately 5.9 acres. A geophysical survey was conducted at the site in 1995, during which two geophysical anomalies were identified. One anomaly is subtle and is not related to known surface/subsurface features, while another is larger and may be related to underground metal piping or fragments. Twelve soil-gas survey samples were collected and analyzed for chlorinated and aromatic volatile organics; PCE was the only target analyte detected. Specific data regarding all site activities may be found in AOC-41 links.
Future plans at the site include completing a record search, field locating and mapping the site, drilling and sampling of soil borings, and collection of surface soil samples. This work is tentatively planned, but it is not currently included in any delivery order. If the site is found to meet RRS1 criteria after this work has been completed, a closure report will be prepared in accordance with TNRCC closure requirements.
AOC-42 is located in the northern portion of the inner cantonment, and has an area of approximately 2.5 acres. A geophysical survey was conducted at the site in 1995, during which four geophysical anomalies were identified. One anomaly may be associated with the trash pile present in the same area, while the other anomalies may be due to additional trenches. Also, fourteen soil-gas survey samples were collected and analyzed for chlorinated and aromatic volatile organics; PCE was the only target analyte detected. Specific data regarding all site activities may be found in AOC-42 links.
Future plans at the site include completing a record search, field locating and mapping the site, drilling and sampling of soil borings, and collection of surface soil samples. This work is tentatively planned, but it is not currently included in any delivery order. If the site is found to meet RRS1 criteria after this work has been completed, a closure report will be prepared in accordance with TNRCC closure requirements.
AOC-43 is located in the north pasture, just south of SWMU B-7, and has an area of approximately 0.6 acre. Three-inch mortar pieces were located at the site in 1996. Based on these pieces, the determination was made that the site was used as a blow hole for detonation of ordnance. UXB completed removal of potential UXO items located at the site in 1997. Specific data regarding all site activities may be found in AOC-43 links.
Future plans at AOC-43 include field locating and mapping the site, conducting a geophysical survey to identify any anomalies, drilling and sampling of soil borings, and collection of surface soil samples. This work is tentatively planned, but it is not currently included in any delivery order. If the site is found to meet RRS1 criteria after this work has been completed, a closure report will be prepared in accordance with TNRCC closure requirements.
AOC-44 is located in the southern portion of the east pasture, and has an area of approximately 0.1 acre. In March 1996, the site was located and site boundaries were surveyed. A geophysical survey was also conducted; one anomaly caused by a large concentration of metal at the surface was identified. Two 20 lb. fragment bombs were located, flagged and removed. An additional geophysical survey identified an additional anomaly, later identified as a deer feeder. Three surface soils were collected; however, the results are currently in question due to ITS’ QA/QC problems. In September 1996, a soil boring was advanced at the site and two soil samples were collected an analyzed for copper. Specific data regarding all site activities may be found in AOC-44 links.
Future plans at AOC-44 include collection of surface soil samples. This work is tentatively planned, but it is not currently included in any delivery order. If the site is found to meet RRS1 criteria after this work has been completed, a closure report will be prepared in accordance with TNRCC closure requirements.
AOC-45 is located in the southwest portion of the inner cantonment, and has an area of approximately 0.1 acre. The site consists of a flat area that contains spent and unspent bullets. Specific data regarding all site activities may be found in AOC-45 links.
Future plans at AOC-45 include field mapping the site, conducting a geophysical survey to identify any anomalies, drilling and sampling of soil borings, and collection of surface soil samples. This work is tentatively planned, but it is not currently included in any delivery order. If the site is found to meet RRS1 criteria after this work has been completed, a closure report will be prepared in accordance with TNRCC closure requirements.
AOC-46 is located in the southwest portion of the inner cantonment adjacent to Building 30, and has an area of approximately 0.1 acre. The site consists of a bermed area with a stockpile of shot potentially containing lead and sand. Specific data regarding all site activities may be found in AOC-46 links.
Stockpiled material at AOC-46 was disposed along with similar waste found at SWMUs B-32 and B-33 under the RL33 project. To address any residual contamination, future plans at AOC-46 include completing field mapping the site, collection of surface soil samples, and if surface soil samples exhibit above-background levels of contamination, drill and sample soil borings. This work is tentatively planned, but it is not currently included in any delivery order. If the site is found to meet RRS1 criteria after this work has been completed, a closure report will be prepared in accordance with TNRCC closure requirements.
AOC-47 is located in the southwest corner of the east pasture, and has an area of approximately 0.3 acre. The site consists of trenches and mounds similar to those observed at SWMU B-15/16. Specific data regarding all site activities may be found in AOC-47 links.
An investigation of the site is planned under the RL83 contract with Parsons ES. Future work planned at the site includes an EM geophysical survey and sampling and analysis of three surface soil samples. If the site is found to meet RRS1 criteria after this work has been completed, a closure report will be prepared in accordance with TNRCC closure requirements.
AOC-48 is located in the southwest corner of the east pasture, and has an area of approximately 2.7 acres. The site consists of three north-south trending mounds and a construction debris pile. It was recently determined that the mounds may have been constructed there for an off-road vehicle training course. Specific data regarding all site activities may be found in AOC-48 links.
An investigation of the site is planned under the RL83 contract with Parsons ES. Future work planned at the site includes an EM geophysical survey and sampling and analysis of three surface soil samples. If the site is found to meet RRS1 criteria after this work has been completed, a closure report will be prepared in accordance with TNRCC closure requirements.
AOC-49 is located in the central portion of the east pasture, and has an area of approximately 0.03 acre. The site consists of one trench, measuring approximately four feet by seven feet. No surface debris has been observed at the site. Specific data regarding all site activities may be found in AOC-49 links.
Future plans at AOC-49 include field mapping the site, conducting a geophysical survey to identify any anomalies, and collection of surface soil samples. If geophysical anomalies or surface soil contamination is observed, soil borings will be drilled and sampled. This work is tentatively planned, but it is not currently included in any delivery order. If the site is found to meet RRS1 criteria after this work has been completed, a closure report will be prepared in accordance with TNRCC closure requirements.
AOC-50 is located in the southwestern portion of the inner cantonment, and has an area of approximately 0.3 acre. The site was located in 1996 during field activities at SWMU B-30, approximately 100 feet away. The site consists of a nickel penetrate area with orange discolored material at the ground surface. Specific data regarding all site activities may be found in AOC-50 links.
Future plans at AOC-50 include field mapping the site, disposing of contaminated soil, and collection of surface soil samples. If surface soil contamination is observed, soil borings will be drilled and sampled. This work is tentatively planned, but it is not currently included in any delivery order. If the site is found to meet RRS1 criteria after this work has been completed, a closure report will be prepared in accordance with TNRCC closure requirements.
AOC-51 is located in the southeast corner of CSSA, in the east pasture. AOC-51 covers approximately 72 acres, and it surrounds SWMU B-9 and AOC-44. UXO items were observed at the site during cedar clearing activities in the spring of 1997. Specific data regarding all site activities may be found in AOC-51 links.
Future plans at AOC-51 include field mapping the site, conducting a geophysical survey to identify any anomalies, a sweep for any remaining UXO, and collection of surface soil samples. This work is tentatively planned, but it is not currently included in any delivery order. If the site is found to meet RRS1 criteria after this work has been completed, a closure report will be prepared in accordance with TNRCC closure requirements.
AOC-52 is located in northeast portion of the inner cantonment, and has an area of approximately 0.1 acre. The site was located in 1995 during a geophysical survey at neighboring SWMU B-4. Three anomalies were found in the area which, at the time, was called B-4A. Two of the three anomalies were caused by trenches and metal debris at the site. Specific data regarding all site activities may be found in AOC-52 links.
Future plans at AOC-52 include field mapping the site, excavating the trenches and removing the metal debris, and collection of soil samples from the trenches. This work is tentatively planned, but it is not currently included in any delivery order. If the site is found to meet RRS1 criteria after this work has been completed, a closure report will be prepared in accordance with TNRCC closure requirements.
AOC-53 is located in the north-central portion of the inner cantonment, and has an area of approximately 0.2 acre. The site consists of a concrete building foundation slab which was used for battery storage. There is no visual evidence of a release. Specific data regarding all site activities may be found in AOC-53 links.
Future plans at AOC-53 include field mapping the site, excavating and disposing of the concrete slab, and collection of three surface soil samples. This work is tentatively planned, but it is not currently included in any delivery order. If the site is found to meet RRS1 criteria after this work has been completed, a closure report will be prepared in accordance with TNRCC closure requirements.
AOC-54 is located in the inner cantonment near the deer processing station, and has an area of approximately 0.2 acre. The site is an area which was used for battery storage. There is stressed vegetation in the area which may be related to battery storage. Specific data regarding all site activities may be found in AOC-54 links.
Future plans at AOC-54 include field mapping the site and collection of surface soil samples. This work is tentatively planned, but it is not currently included in any delivery order. If the site is found to meet RRS1 criteria after this work has been completed, a closure report will be prepared in accordance with TNRCC closure requirements.
AOC-55 is located in the northeast portion of the inner cantonment adjacent to Salado Creek, and has an area of approximately 0.4 acre. The site was potentially used as a landfill. Specific data regarding all site activities may be found in AOC-55 links.
Future plans at AOC-55 include field mapping the site, conducting a geophysical survey, drilling and sampling of soil borings, and collection of surface soil samples. This work is tentatively planned, but it is not currently included in any delivery order. If the site is found to meet RRS1 criteria after this work has been completed, a closure report will be prepared in accordance with TNRCC closure requirements.
AOC-56 is located in the southeast corner of the inner cantonment, and has an area of approximately 0.2 acre. The site was potentially used as a construction debris landfill. Specific data regarding all site activities may be found in AOC-56 links.
An investigation of the site is planned under the RL83 contract with Parsons ES. Future work planned at the site includes an EM geophysical survey and sampling and analysis of three surface soil samples. If the site is found to meet RRS1 criteria after this work has been completed, a closure report will be prepared in accordance with TNRCC closure requirements.
AOC-57 is located in the southwest portion of the inner cantonment, and has an area of approximately 6.3 acres. The site is long and thin and is situated along a gravel road. The site was used for cleaning and maintenance activities at temporary structures. Specific data regarding all site activities may be found in AOC-57 links.
Future plans at AOC-57 include field mapping the site and collection of surface soil samples. This work is tentatively planned, but it is not currently included in any delivery order. If the site is found to meet RRS1 criteria after this work has been completed, a closure report will be prepared in accordance with TNRCC closure requirements.
AOC-58 is located in the northeast portion of the inner cantonment proximate to MW2, and has an area of approximately 0.2 acre. The site is a suspected trench which was observed on a 1973 aerial photograph. Specific data regarding all site activities may be found in AOC-58 links.
An investigation of the site is planned under the RL83 contract with Parsons ES. Future work planned at the site includes an EM geophysical survey and sampling and analysis of three surface soil samples. If the site is found to meet RRS1 criteria after this work has been completed, a closure report will be prepared in accordance with TNRCC closure requirements.
AOC-59 is located in the east pasture, and has an area of approximately 0.2 acre. The site is a suspected trench observed in a 1966 aerial photograph. Specific data regarding all site activities may be found in AOC-59 links.
Future plans at AOC-59 include field mapping the site, conducting a geophysical survey, drilling and sampling soil borings, and collection of surface soil samples. This work is tentatively planned, but it is not currently included in any delivery order. If the site is found to meet RRS1 criteria after this work has been completed, a closure report will be prepared in accordance with TNRCC closure requirements.
AOC-60 is located in the southwest portion of the east pasture, and has an area of approximately 0.6 acre. The site is a suspected trench observed in a 1966 aerial photograph. Specific data regarding all site activities may be found in AOC-60 links.
Future plans at AOC-60 include field mapping the site, conducting a geophysical survey, drilling and sampling soil borings, and collection of surface soil samples. This work is tentatively planned, but it is not currently included in any delivery order. If the site is found to meet RRS1 criteria after this work has been completed, a closure report will be prepared in accordance with TNRCC closure requirements.
AOC-61 is located in the northeast portion of the inner cantonment at Tenberg and East Outer Roads, and has an area of approximately 1.0 acre. The site is a suspected trench which was observed on a 1966 aerial photograph. Specific data regarding all site activities may be found in AOC-61 links.
An investigation of the site is planned under the RL83 contract with Parsons ES. Future work planned at the site includes an EM geophysical survey and sampling and analysis of three surface soil samples. If the site is found to meet RRS1 criteria after this work has been completed, a closure report will be prepared in accordance with TNRCC closure requirements.
AOC-62 is located in the northeast portion of the inner cantonment, and has an area of approximately 0.4 acre. AOC 62 is located south of SWMU B-28, east of Salado Creek, and west of monitoring well MW-2. The site was located in 1995 during a geophysical survey. Specific data regarding all site activities may be found in AOC-62 links.
Future plans at AOC-62 include field mapping the site, conducting a geophysical survey to better define and confirm previous results, and collection of surface soil samples. This work is tentatively planned, but it is not currently included in any delivery order. If the site is found to meet RRS1 criteria after this work has been completed, a closure report will be prepared in accordance with TNRCC closure requirements.
AOC-63 is located in the east pasture, and has an area of approximately 1.0 acre. Three drums containing rocks are located at the site. The origin of the drums and what they may have been used for is not known. Specific data regarding all site activities may be found in AOC-63 links.
Future plans at AOC-63 include field mapping the site, sampling the drum contents, properly disposing of the drums, and collection of surface soil samples if the drums are found to contain contaminants. This work is tentatively planned, but it is not currently included in any delivery order. If the site is found to meet RRS1 criteria after this work has been completed, a closure report will be prepared in accordance with TNRCC closure requirements.
AOC-64 is located in the northeast portion of the inner cantonment, east of SWMU B-4, and has an area of approximately 0.1 acre. Aerial flares, devices similar to those disposed of at B-28, have been identified on the ground surface in this area. The origin of the flares is not known. Specific data regarding all site activities may be found in AOC-64 links.
Future plans at AOC-64 include field mapping the site, properly disposing of the flares, and collection of surface soil samples. This work is tentatively planned, but it is not currently included in any delivery order. If the site is found to meet RRS1 criteria after this work has been completed, a closure report will be prepared in accordance with TNRCC closure requirements.
AOC-65 is located in Building 90. This area of concern is a sunken concrete-lined pit that housed a vat that held TCE. The metal vat (approximately 500 to 750 gallons) was installed prior to 1966 and removed in 1995 when CSSA began using a citrus- based cleaner for operations, instead of the TCE. The concrete vat was covered with a metal plate welded in place. Specific data regarding all site activities may be found in AOC-65 links.
Future plans at AOC-65 include removing the welded metal plate, coring through the concrete floor of the concrete-lined pit, and collecting soil samples beneath the concrete floor to ensure that contaminants from the removed vat did not leak or spill into the concrete-lined pit and contaminate the soil. This work is tentatively planned, but it is not currently included in any delivery order. If the site is found to meet RRS1 criteria after this work has been completed, a closure report will be prepared in accordance with TNRCC closure requirements.
AOC-66 is located in the North Pasture, just north of well 16. This area of concern is south of SWMUs B-1 and B-2. AOC-41 is to the east and AOC-35 is to the south. Soil gas surveys were conducted in all of the surrounding areas in 1995, but no survey was done in the area which is denoted as AOC-66. Specific data regarding all site activities may be found in AOC-66 links.
Future plans at AOC-66 include a soil gas survey to ensure that low levels of contaminants in soil gas in surrounding areas do not extend to AOC-65. This work is tentatively planned, but it is not currently included in any delivery order. If the site is found to meet RRS1 criteria after this work has been completed, a closure report will be prepared in accordance with TNRCC closure requirements.
AOC-67 is a drainage ditch located east of Building 90-1. Ordnance maintenance activities took place in Building 90-1. Rinsates and floor residues were pumped from Building 90-1 into a 1250 gallon aboveground tank which was located beside the ditch. The tank was removed in approximately 1997. The tank contents were historically dumped into the oxidation pond when the tank was full. It is unknown if there were any releases to the drainage area. The dimensions of the ditch are approximately 100 feet by 20 feet. Specific data regarding all site activities may be found in AOC-67 links.
Future plans at AOC-67 include the drilling and sampling of three borings (two in the ditch and one in the concrete pad that the tank rested on) to a depth of 4 feet to determine if metals have leached. The soils will also be tested for analytes detected at the oxidation pond. This work is tentatively planned, but it is not currently included in any delivery order. If the site is found to meet RRS1 criteria after this work has been completed, a closure report will be prepared in accordance with TNRCC closure requirements.
AOC-68 is located in a drainage swale on the /northwest side of Building 90-2. The drainage swale has an area of approximately 10 feet by 10 feet. There is surficial hardened metallic debris on the ground outside of the building from wheelabrator operations. Specific data regarding all site activities may be found in AOC-68 links.
Future plans at AOC-68 include the removal of the top one-foot of soil material from the area, drilling and sampling of three borings to a depth of 10 feet to determine if metals and/or oils and greases have leached. Approximately three confirmation samples will also be collected in the surrounding soils. This work is tentatively planned, but it is not currently included in any delivery order. If the site is found to meet RRS1 criteria after this work has been completed, a closure report will be prepared in accordance with TNRCC closure requirements.
The Coal Bins are located in the inner cantonment, northwest of the headquarters building. This site was reportedly utilized as a bulk coal storage area. A request to delist this site will be submitted to TNRCC. Specific data regarding all site activities may be found in the Coal Bins link.