Anonymous Public Comment

These comments are provided by a worker in the forging industry for more than 10 years. The level of sophistication of the mass balance accounting system to determine whether a company falls under this standard is beyond the capabilities of the companies within the forging industry. Companies process hundreds of grades of steel and alloys, each with a unique chemistry, every year. To start with, the mass balance has multiple parts beginning with the cutting operation. For the cutting operation the mass balance is: Ingot starting weight - product weight - ingot tops sent to scrap - stock returned to inventory = material lost during cutting operation. Cutting operations consist of dry sawing with a carbide saw (dust producer), wet saw operations with a band saw (uses coolant typically, no dust), and torch cutting. Torch cutting is newer to the industry and can cut up to a 30" dia ingot in a fraction of what saw cutting requires. It melts/vaporizes a 3/8" wide section of the ingot as it cuts producing significant fume/dust as well as slag. Determining the amount/composition of slag created would be very difficult, thus making the mass balance highly inaccurate. Torching was not even discussed in the standard. After a piece is cut, it is heated in a furnace. During the heating process, scale is formed on the part. Scale is a material similar to a piece of rust. Oxygen in the steel migrates to the surface and oxidizes the outer layer of metal. When the piece of steel is removed from the furnace, some scale falls off. The scale breaks a part very easily into dust size particles. This can be 1-3% of the initial piece weight. The longer a piece stays in the furnace, the more scale forms. Once heated, the part is removed from the furnace and forged. The compression of the forging process creates significant scale as well. Scale is swept up and emptied into hoppers throughout the day and sent out with the scrap. However, because it is so friable, accounting for an airborne dust component that makes it out of the building to the environment would be impossible and then on top of that figuring out its composition because of all the different grades processed in a day makes it doubly impossible. The dust levels / concentrations inside of the building are already regulated by OSHA standards and do not need to be part of this standard. Often forgings require on the spot grinding or torching to remove cracks while the part is being processed. Removing it to a centralized location that has a dust collection system not only is inefficient, but the part is cooling down and will likely need to be reheated before being processed further. This will increase natural gas consumption leading to additional pollutants and green house gasses being emitted by the facility. Once a piece is forged, it is heat treated. The heat treating process also is a scale producing process with the same concerns for mass accounting as listed above. Once heat teated, a part is machined. The proposed standard suggests that typically this is done in an enclosed system. This is not accurate. The vast majority of systems are open to the atmosphere and cannot be enclosed because of their control systems. These are the machines that have to cut through the scale left on the part by the heat treating and forging process. Again, determining the amount of dust created by machining and then determining how much actually escapes the building is an impossible task because of the dust settling in various locations within the building. In conclusion, determining the amount of regulated PM emissions from forging industry operations that actually escape the building to the environment in terms of quantity and composition is not practical or feasible. The airborne components tend to seltle quickly as well making their impact outside property lines less likely. Because of its impractical/impossible mass balance accounting requirements that will lead to signficant inaccuacies, the forging industry should not be included in this standard until EPA can determine a better method of determining emissions for our industry. Thank you.