Document Qg22L3Z3JXw1DkbRMMxV73Xz6

salt coating during the bluing process. The bluing process includes cleaning, polishing, rinsing metal components, and immersing them in a solution of black oxide salt, to produce a decorative color finish. Metal components also go through a case hardening process where the metal is heat treated so the surface of the metal component is hardened, while keeping the underlying metal layer ductile. The facility operates four days a week and produces between 300-350 rifles per year. The bluing process starts by taking various types of steel stock and creating the steel components needed to fabricate the Sharps rifle. The facility has four computer numerical control (CNC) machines that cut the steel stock to the desired specifications. Used oil from the CNC machines is collected and given to local shops to burn in oil heaters during the winter months. Some steel components undergo a bluing process (barrels, screws) while other components undergo a case hardening process (screws, fasteners, firing pins, bolts). For the bluing process, the steel components are first cleaned with acetone, then placed into a 70-gallon tank with a Du-Lite soap solution bath which is heated to 150 degrees Fahrenheit. Next, the steel components are rinsed with water in a different 70-gallon tank bath that is also heated to 150 degrees Fahrenheit. The hot rinse water overflows to a 40-gallon tank with a sump pump. After the steel components are cleaned and rinsed, the components are placed in a separate 70-gallon tank where they are soaked in a black oxide salt bath (which is composed of Du-Lite Steelkote) for up to 20 minutes; a separate 35-gallon tank is used for smaller steel components. This black oxide salt bath is continuously replenished with tap water to maintain a constant temperature, and the addition of black oxide salts when needed. The components are then rinsed with cold water in a 70-gallon non-heated rinse tank. The cold-water rinse overflows to the 40-gallon tank with a sump pump. Parts are transferred from one tank to the next via metal baskets; the tanks are close enough that there is little dripping between tanks. Any liquid hitting the floor would be contained in the area due to the floor drain being plugged. The bluing process line is operated approximately once every two weeks. The metal components which undergo the case hardening process are first cleaned with acetone and then heat treated in an oven containing sodium cyanide. Sodium cyanide is heated in an oven until it turns to liquid, metal components are heated enough that they begin to absorb carbon from the sodium cyanide. The additional carbon enters the crystalline structure of the surface of the metal, and hardens when cooled, or quenched. This leaves the surface of the metal component hard, while the interior characteristics of the metal do not change. Depending on the length of time the metal component is exposed to the sodium cyanide, the process will prevent corrosion and provide a decorative finish. Once the oven cools, the sodium cyanide returns to solid form and is reused. Spent sodium cyanide, in ash form, is placed in a drum and is recycled when full. The drum is hauled offsite by a contractor, Safety Kleen as needed but approximately once annually. Once the metal components are removed from the oven, they are submerged in a quench tank containing water. The quench tank helps to rapidly cool the heat-treated steel components and develop the desired color. When the process is complete, all rinse water/overflow collected in the 40-gallon tank with a sump pump, is pumped into a 750-gallon storage tank. The 40-gallon tank has a high and low float valve for activating pumping. The storage tank is gravity fed into a gas fired boil out tank with an automatic float valve that adds water as it boils into steam. All treated steel components are then assembled with wooden components to form the final product. Shiloh Sharps, Inc. - ID# MTPF000101 NPDES Pretreatment Categorical Industrial User Page 4 of 6 Records After the facility representative provided a background description of the facility operations, the inspector asked to see records to include transfer logs for waste materials transferred off-site, standard operating procedures (SOP) for the bluing, case hardening, and boil out operations, and Material Safety Data Sheets for chemicals kept on-site. The facility has an SOP and has changed its process to eliminate the potential for a slug discharge through the addition of a boil out tank to convert all effluent water to steam. The facility is not required to maintain a Slug Discharge Control Plan with current operations. The facility is currently under an Administrative Order on Consent ( ) which requires the issuance of a Notice of Discharge Requirements before the Administrative Order on Consent can be closed out. The facility was provided an application form on April 30, 2024, as part of the March 27, 2024, compliance evaluation inspection report. stated has started the process of completing the application; however, has some questions and concerns with the information required. The inspector stated would have EPA's pretreatment coordinator reach out and provide assistance. Site visit After facility representative interviews and records review, walked the inspector around each of the processes. We started in the manufacturing area, where there were multiple worktables, tools, CNC machines, barrel drilling machines, and other large pieces of equipment used to manufacture the various steel components used in the Sharps rifle. stated the raw materials used at the facility primarily include black walnut wood and various types of steel stock (e.g., barrel stock, screw stock). Next, we entered the east side of the building where the bluing and case hardening operations occur. The room is set up where the bluing process is on the east side of the room and the case hardening process is on the west side of the room. The bluing process includes a line of five tanks: a soap bath and hot water rinse (photo 167), two bluing tanks (one for larger parts and one for smaller parts) (photos 166 & 170), and a cold rinse water tank (photo 166). The soap tank and two bluing tanks are not drained between batches. The hot water rinse tank and the cold-water rinse tank have overflows on the back of the tanks that send overflow water during the process to the 40-gallon sump tank located behind the hot rinse tank (photos 168 & 169). The hot water rinse tank and cold-water rinse tank are drained after each batch; water is discharged into the 40-gallon sump tank and to the boiler tank (photo 173). The case hardening operation includes an oven containing sodium cyanide (photo 171) and two coldwater quench tanks (photo 172). The quench tanks are continually replenished with water during the process. The quench tanks are discharged via a siphon hose across the room to the cold-water rinse tank in the bluing process, which then discharges into the sump tank, and ultimately to the boiler tank. There is a floor drain located in the center east of the bluing room which is connected to the City of Big Timber's POTW. However, the drain has a plug in it which is located under a plate (subsurface) and is screwed into the drain piping; the drain is constantly plugged. Facility staff would only unscrew the plug if the emergency eye wash and/or shower are used. The sump tank (photos 168 & 169) is on a high-level float system to pump contents of the tank to a 750-gallon boiler storage tank in the evaporation room (photo 173). The storage tank has a shut-off valve, but when opened, water is fed via gravity into a gas fired boil out tank with an automatic float valve that adds water as it boils into steam (photo 174). The steam is released outside of the building. Shiloh Sharps, Inc. - ID# MTPF000101 NPDES Pretreatment Categorical Industrial User Page 5 of 6 The chemicals are stored in the evaporation room on the south side where there is no floor drain. All chemical drums are marked and are set on wooden pallets. Used oil from the CNC machines is collected and given to local shops to burn in oil heaters during the winter months to produce heat. Closing and Follow-Up A closing conference was held on-site with , during which the process for the inspection report was discussed. The inspection concluded at 0945. Shiloh Sharps, Inc. - ID# MTPF000101 NPDES Pretreatment Categorical Industrial User Page 6 of 6