Coating Materials News Vol 7 Issue 1
January - March, 1997
Waste Management Considerations in Vacuum Deposition Processes
by Gerard E. Manley
Safety and Environmental Manager
Nothing in this article should be construed as legal advice. It is for informational purposes only. Each generator of waste is ultimately responsible for evaluation of all federal, state and local regulations to determine proper classification of the waste and the applicability of regulations to your business in order to identify appropriate actions necessary for compliance. At the international level, it is important to understand the regulations of the specific country in which you are dealing.
One aspect of the vacuum deposition process that this newsletter has yet to address is the issues involving waste management. Whereas the readers of this newsletter are technically knowledgeable in the theory and application of thin film technology, this same group may likely be less knowledgeable of the often confusing regulations governing proper generation, transportation and disposal of wastes created from these processes. While the intent is not to make anyone an expert, it is beneficial to understand the fundamental concepts of waste management. This initial article will focus on what makes a waste a regulated hazardous waste. Future newsletters will focus on regulatory obligations of generators of hazardous waste.
At the federal level, the agency primarily responsible for developing regulations governing the protection of the environment is the Environmental Protection Agency. Formed as an independent Administrative Agency within the Executive Branch in 1970, EPA was directed by Congress to establish regulations overseeing the management of solid and hazardous wastes following the 1976 promulgation of the Resource Conservation and Recovery Act (RCRA).
RCRA identifies the minimum requirements that State regulatory agencies must enforce for the management of solid and hazardous wastes. Each individual state has the authority to go beyond RCRA, enacting stricter standards as it deems appropriate. Each business must evaluate the specific state, and in some cases, local regulations to fully understand the regulatory burden of which compliance is expected.
An excellent starting point in understanding hazardous waste management issues is to first properly identify the "waste streams" generated by your processes. Waste stream is the term used to identify each individual source of waste, be it from the installation, start-up, operation, or cleaning of a process. It is important to understand in detail the physical and chemical nature of each waste stream. While many waste streams may be obvious, it is very easy to overlook some waste streams that ultimately may need to be managed as a hazardous waste.
Examples of typical waste streams from vacuum deposition include:
- Spent coating materials and their source containers. (i.e. boats, filaments, crucibles, liners, sputtering targets, cathodes, etc.)
- Masking materials, such as aluminum foil, used to shield the chamber interior
- Sand from sandblast cleaning of tooling, or wipe-down sand paper and towels, either dry or solvent soaked
- Scrap coated optical or metal pieces
- Used solder from metallic bonding of targets to backing plates
Once all of the waste streams are identified and the physical and chemical nature of these streams are "characterized", it is then appropriate to evaluate the applicable regulations to determine which waste streams must be managed as hazardous waste.
Criteria for Identifying Hazardous Waste:
EPA Regulations are compiled in the Code of Federal Regulations at Chapter 40 (40 CFR). Specific regulations concerning hazardous waste management begin at 40 CFR Part 260. Part 261 addresses the identification and listing of hazardous waste.
Within these regulations you can find detailed and often complicated definitions of common terminology used in Hazardous Waste Management. In addition, numerous exemptions and exceptions to specific regulations are listed. Developing a working knowledge of this information is important for the personnel responsible for managing hazardous waste within your business. This article attempts only to provide a general understanding of the major driving forces within this regulation.
Waste may be classified as hazardous waste by either exhibiting a defined characteristic of hazardous waste (Part 261 Subpart C) or by being specifically listed as a hazardous waste on one or more of numerous lists (Part 261 Subpart D).
Characteristics of hazardous waste include the following: ignitability, corrosivity, reactivity, and toxicity.
Heavy Metal Wastes:
Among the representative waste streams for vacuum deposition processes previously noted, the attribute of primary concern is that of toxicity. A procedure entitled the Toxicity Characteristic Leaching Procedure (TCLP) test is used to determine if a waste must be managed as a hazardous waste due to toxicity. Table 1 of Part 262.24 identifies the contaminants and the regulatory limits for the TCLP.
Contaminants of particular concern to the vacuum deposition industry in the following Table are the "heavy metals". Of the 40 contaminants listed, 8 are inorganic and the remaining 32 are organic. The inorganic contaminants and the regulatory level for the TCLP test are listed in the adjacent table.
|TCLP Regulatory Levels for Inorganic Constituents|
|As a result, any waste that has as a constituent or has the potential to be contaminated with a material containing any of the metals listed should be evaluated to determine if it would fail a TCLP test by exceeding the noted regulatory level. If so, it likely must be managed as a hazardous waste.
While the focus of the Toxicity Characteristic for our industry is on the heavy metals, it is important that each business evaluate the organic contaminants on this list to determine if any wastes are regulated based on its organic constituents.
Other Characteristics of Waste:
Ignitable wastes include those wastes which 1) have a flash point < 60°="" c;="" or="" 2)="" are="" capable="" of="" causing="" fire="" through="" friction,="" absorption="" of="" moisture,="" or="" spontaneous="" chemical="" change="" and,="" when="" ignited,="" burns="" so="" vigorously="" and="" persistently="" that="" it="" creates="" a="" hazard;="" or="" 3)="" it="" is="" an="" ignitable="" compressed="" gas;="" or="" 4)="" it="" is="" an="" oxidizer.="">
Based on this definition, some metal powders which are flammable and/or moisture sensitive may, as a constituent of a waste, be managed as a RCRA hazardous waste. One example is aluminum powder or other metal dusts from deposition processes. In addition, waste solvents used in the cleaning process such as acetone or ethanol would exhibit this characteristic.
Corrosive wastes include those liquid wastes which 1) exhibit a pH of 2 or 12.5; or 2) a liquid that corrodes steel at a specified rate.
While not a prominent issue within the industry, it is important to consider corrosive cleaning or etching wastes within this category.
A waste must be managed as a Reactive Waste if it 1) is normally unstable and readily undergoes violent change without detonation; 2) reacts violently with water; 3) forms potentially explosive mixtures with water; or 4) when mixed with water, it generates toxic gases, vapors or fumes in quantity sufficient to present a danger to human health or the environment.
Several inorganic wastes could be classified within this characteristic due to violent reactions with water, or the generation of toxic or explosive mixtures following contact with moisture. This characteristic may include some sulfides, hydrides, fluorides, chlorides and elemental metal powders
The "F-List" identifies hazardous waste from non-specific sources. The "K-List" identifies hazardous waste from specific sources. The "P-List" and the "U-List" identify numerous organic and inorganic compounds, which if disposed of as "discarded commercial chemical products, off-specification species, container residues, and spill residues..." must be managed as a hazardous waste.
Exclusions, Exemptions, Exceptions:
Almost all of these exceptions are very specific, and the applicability of these exceptions are very strict. It is important that all conditions are clearly met prior to utilizing any of these exceptions to limit regulatory burden and/or costs.
Future articles will cover requirements for managing hazardous waste prior to shipping off-site, along with treatment and disposal options for typical waste materials generated in coating applications. If there are any other specific topics involving hazardous waste management that you are interested in seeing addressed in this newsletter, feel free to contact us via e-mail (firstname.lastname@example.org) or call us directly at (414) 289-9800.
Dr. Ervin Colton, Editor
P.O. Box 1178 | Milwaukee, WI 53201
Phone: 414-289-9800 | FAX: 414-289-9805
Samuel Pellicori, Principal Contributor
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