13.1 Introduction 486
13.2 Hazardous Waste Identification Process 486
13.3 Exclusions from Solid and Hazardous Wastes 487
13.3.1 Recycled Materials 488
13.3.2 Secondary Materials 489
13.3.3 Sham Recycling 491
13.3.4 Exemptions from Hazardous Wastes 491
13.4 Definition of Hazardous Waste 498
13.4.1 Hazardous Waste Listings 498
13.4.2 Hazardous Waste Characteristics 499
13.4.3 Listed Hazardous Wastes 500
13.4.4 Listing Criteria 501
13.4.5 The F List: Wastes from Nonspecific Sources 502
13.4.6 The K List: Wastes from Specific Sources 505
13.4.7 The P and U Lists: Discarded Commercial Chemical Products 505
13.5 Characteristic Hazardous Wastes 506
13.5.1 Ignitability 507
13.5.2 Corrosivity 507
13.5.3 Reactivity 507
13.5.4 Toxicity Characteristics 508
13.6 Wastes Listed Solely for Exhibiting the Characteristic of Ignitability,
Corrosivity, or Reactivity 510
13.7 The Mixture and Derived-from Rules 510
13.7.1 Background 510
13.7.2 Listed Hazardous Wastes 510
13.7.3 Characteristic Wastes 511
13.7.4 Waste Listed Solely for Exhibiting the Characteristic of Ignitability, Corrosivity, or Reactivity 511
13.7.5 Mixture Rule Exemptions 512
13.7.6 Derived-from Rule Exemptions 512
13.7.7 Delisting 513
13.8 The Contained-in Policy 513
13.9 Regulatory Developments 515
13.9.1 The Hazardous Waste Identification Rules 515
13.9.2 Final Hazardous Waste Listing Determinations 515
13.9.3 Proposed Revision to Wastewater Treatment Exemption for
Hazardous Waste Mixtures 516
The improper management of hazardous waste poses a serious threat to both the health of people and the environment. When the United States Environmental Protection Agency (U.S. EPA) began developing the hazardous waste management regulations in the late 1970s, the Agency estimated that only 10% of all hazardous waste was managed in an environmentally sound manner.
Proper identification of a hazardous waste can be a difficult and confusing task, as the Resource Conservation and Recovery Act (RCRA) regulations establish a complex definition of the term "hazardous waste." To help make sense of what is and is not a hazardous waste, this chapter presents the steps involved in the process of identifying, or "characterizing," a hazardous waste.
This chapter will introduce the entire hazardous waste identification process, but will focus particularly on the final steps and the characteristics and properties of hazardous wastes. After reading this chapter, one will be able to understand the hazardous waste identification process and the definition of hazardous waste, and be familiar with the following concepts:
1. Hazardous waste listings
2. Hazardous waste characteristics
3. The "mixture" and "derived-from" rules
4. The "contained-in" policy
5. The Hazardous Waste Identification Rules (HWIR)
A hazardous waste is a waste with a chemical composition or other properties that make it capable of causing illness, death, or some other harm to humans and other life forms when mismanaged or released into the environment.1 Developing a regulatory program that ensures the safe handling of such dangerous wastes, however, demands a far more precise definition of the term. U.S. EPA therefore created a series of hazardous waste identification regulations, which outline the process to determine whether any particular material is a hazardous waste for the purposes of RCRA.
Proper hazardous waste identification is essential to the success of the hazardous waste management program. The RCRA regulations require that any person who produces or generates a waste must determine if that waste is hazardous. For this purpose, the RCRA includes the following steps in the hazardous waste identification process2:
1. Is the waste a "solid waste"?
2. Is the waste specifically excluded from the RCRA regulations?
3. Is the waste a "listed" hazardous waste?
4. Does the waste exhibit a characteristic of hazardous waste?
Hazardous waste identification begins with an obvious point: in order for any material to be a hazardous waste, it must first be a waste. However, deciding whether an item is or is not a waste is not always easy. For example, a material (like an aluminum can) that one person discards could seem valuable to another person who recycles that material. U.S. EPA therefore developed a set of regulations to assist in determining whether a material is a waste. RCRA uses the term "solid waste" in place of the common term "waste." Under RCRA, the term "solid waste" means any waste, whether it is a solid, semisolid, or liquid. The first section of the RCRA hazardous waste identification regulations focuses on the definition of solid waste. For this chapter, you need only understand in general terms the role that the definition of solid waste plays in the RCRA hazardous waste identification process.
Only a small fraction of all RCRA solid wastes actually qualify as hazardous wastes. According to U.S. EPA estimates, of the 12 billion tons (metric) of industrial, agricultural, commercial, and household wastes generated annually, 254 million tons (2%) are hazardous, as defined by RCRA regulations.3 At first glance, one would imagine that distinguishing between hazardous and non-hazardous wastes is a simple matter of chemical and toxicological analysis. Other factors must be considered, however, before evaluating the actual hazard posed by a waste's chemical composition. Regulation of certain wastes may be impractical, unfair, or otherwise undesirable, regardless of the hazards they pose. For instance, household waste can contain dangerous chemicals, such as solvents and pesticides, but making households subject to the strict RCRA waste management regulations would create a number of practical problems. Congress and U.S. EPA have exempted or excluded certain wastes, including household wastes, from the hazardous waste definition and regulations. Determining whether or not a waste is excluded or exempted from hazardous waste regulation is the second step in the RCRA hazardous waste identification process. Only after determining that a solid waste is not somehow excluded from hazardous waste regulation should the analysis proceed to evaluate the actual chemical hazard of a waste.
The final steps in the hazardous waste identification process determine whether a waste poses a sufficient chemical or physical hazard to merit regulation. These steps in the hazardous waste identification process involve evaluating the waste in light of the regulatory definition of hazardous waste. The remainder of this chapter explains the definition, characteristics, and properties of hazardous wastes.
The statutory definition points out that whether a material is a solid waste is not based on the physical form of the material (i.e., whether or not it is a solid as opposed to a liquid or gas), but rather that the material is a waste. The regulations further define solid waste as any material that is discarded by being either abandoned, inherently waste-like, a certain military munition, or recycled (Figure 13.1). These terms are defined as follows:
1. Abandoned. This simply means "thrown away." A material is abandoned if it is disposed of, burned, or incinerated.
2. Inherently waste-like. Some materials pose such a threat to human health and the environment that they are always considered solid wastes; these materials are considered to be inherently waste-like. Examples of inherently waste-like materials include certain dioxin-containing wastes.
Is material discarded by being either
• Inherently waste-like?
• A discarded military munition?
Material is not a solid waste and is not subject to RCRA Subtitle C regulation
Material is a solid waste and may be a hazardous waste subject to RCRA Subtitle C regulation
FIGURE 13.1 Determination of whether a waste is a solid waste. Source: U.S. EPA, Resource Conservation and Recovery Act—Orientation Manual, Report EPA 530-R-02-016, U.S. EPA, Washington, DC, January 2003.
3. Military munitions. Military munitions are all ammunition products and components produced for or used by the U.S. Department of Defense (DOD) or U.S. Armed Services for national defense and security. Unused or defective munitions are solid wastes when abandoned (i.e., disposed of, burned, incinerated) or treated prior to disposal; rendered nonrecyclable or nonuseable through deterioration; or declared a waste by an authorized military official. Used (i.e., fired or detonated) munitions may also be solid wastes if collected for storage, recycling, treatment, or disposal.
4. Recycled. A material is recycled if it is used or reused (e.g., as an ingredient in a process), reclaimed, or used in certain ways (used in a manner constituting disposal, burned for energy recovery, or accumulated speculatively).
Materials that are recycled are a special subset of the solid waste universe. When recycled, some materials are not solid wastes, and therefore not hazardous wastes, but others are solid and hazardous waste, but are subject to less-stringent regulatory controls. The level of regulation that applies to recycled materials depends on the material and the type of recycling (Figure 13.2). Because some types of recycling pose threats to human health and the environment, RCRA does not exempt all recycled materials from the definition of solid waste. As a result, the manner in which a material is recycled will determine whether or not the material is a solid waste, and therefore whether it is
Is waste recycled by being
• Used as a product substitute?
• Returned to the production process?
Is waste reclaimed?
Is recycled waste
■ Used in a manner constituting disposal?
■ Burned for energy recovery, used to produce a fuel, or contained in fuels?
• Accumulated speculatively?
■ A dioxin-containing waste considered inherently waste-like?
Is recycled waste
■ Used in a manner constituting disposal?
■ Burned for energy recovery, used to produce a fuel, or contained in fuels?
• Accumulated speculatively?
■ A dioxin-containing waste considered inherently waste-like?
Facility must determine if waste is a
• Spent material
• Commercial chemical product Scrap metal
Waste is not a solid waste
Facility must determine if waste is a
• Spent material
• Commercial chemical product Scrap metal
FIGURE 13.2 Determination of whether recycled wastes are hazardous wastes. Source: U.S. EPA, Resource Conservation and Recovery Act—Orientation Manual, Report EPA 530-R-02-016, U.S. EPA, Washington, DC, January 2003.
regulated as a hazardous waste. In order to encourage waste recycling, RCRA exempts three types of wastes from the definition of solid waste2:
1. Wastes used as an ingredient. If a material is directly used as an ingredient in a production process without first being reclaimed, then that material is not a solid waste.
2. Wastes used as a product substitute. If a material is directly used as an effective substitute for a commercial product (without first being reclaimed), it is exempt from the definition of solid waste.
3. Wastes returned to the production process. When a material is returned directly to the production process (without first being reclaimed) for use as a feedstock or raw material, it is not a solid waste.
Materials, however, are solid wastes and are not exempt if they are recycled in certain other ways. For example, materials recycled in the following ways are defined as solid wastes:
1. Waste used in a manner constituting disposal. Use constituting disposal is the direct placement of wastes or products containing wastes (e.g., asphalt with petroleum-refining wastes as an ingredient) on the land.
2. Waste burned for energy recovery, used to produce a fuel, or contained in fuels. Burning hazardous waste for fuel (e.g., burning for energy recovery) and using wastes to produce fuels are regulated activities. However, commercial products intended to be burned as fuels are not considered solid wastes. For example, off-specification jet fuel (e.g., a fuel with minor chemical impurities) is not a solid waste when it is burned for energy recovery, because it is itself a fuel.
3. Waste accumulated speculatively. In order to encourage recycling of wastes as well as to ensure that materials are recycled and not simply stored to avoid regulation, U.S. EPA established a provision to encourage facilities to recycle sufficient amounts in a timely manner. This provision designates as solid wastes those materials that are accumulated speculatively. A material is accumulated speculatively (e.g., stored in lieu of expeditious recycling) if it has no viable market or if the person accumulating the material cannot demonstrate that at least 75% of the material is recycled in a calendar year, commencing on January 1.
4. Dioxin-containing wastes considered inherently waste-like. Dioxin-containing wastes are considered inherently waste-like because they pose significant threats to human health and the environment if released or mismanaged. As a result, RCRA does not exempt such wastes from the definition of solid waste even if they are recycled through direct use or reuse without prior reclamation. This is to ensure that such wastes are subject to the most protective regulatory controls.
Not all materials can be used directly or reused without reclamation. A material is reclaimed if it is processed to recover a usable product (e.g., smelting a waste to recover valuable metal constituents), or if it is regenerated through processing to remove contaminants in a way that restores them to their useable condition (e.g., distilling dirty spent solvents to produce clean solvents). If secondary materials are reclaimed before use, their regulatory status depends on the type of material. For this solid waste determination process, U.S. EPA groups all materials into five categories: spent materials, sludges, byproducts, commercial chemical products (CCPs), and scrap metal.
Spent materials are materials that have been used and can no longer serve the purpose for which they were produced without processing. For example, a solvent used to degrease metal parts will eventually become contaminated such that it cannot be used as a solvent until it is regenerated. If a spent material must be reclaimed, it is a solid waste and is subject to hazardous waste regulation. Spent materials are also regulated as solid wastes when used in a manner constituting disposal, when burned for energy recovery, when used to produce a fuel or contained in fuels, or when accumulated speculatively (see Table 13.1).
Sludges are any solid, semisolid, or liquid wastes generated from a wastewater treatment plant, water supply treatment plant, or air pollution control device (e.g., filters, baghouse dust). Sludges from specific industrial processes or sources (known as listed sludges) are solid wastes when reclaimed, when used in a manner constituting disposal, when burned for energy recovery, used to produce a fuel, or contained in fuels, or when accumulated speculatively. On the other hand, characteristic sludges (those that exhibit certain physical or chemical properties) are not solid wastes when reclaimed, unless they are used in a manner constituting disposal, are burned for energy recovery, used to produce a fuel, or contained in fuels, or are accumulated speculatively (Table 13.1).
Byproducts are materials that are not one of the intended products of a production process. An example is the sediment remaining at the bottom of a distillation column. Byproduct is a catch-all term and includes most wastes that are not spent materials or sludges. Listed byproducts are solid wastes when reclaimed; used in a manner constituting disposal; burned for energy recovery, used to produce a fuel, or contained in fuels; or accumulated speculatively. On the other hand, characteristic byproducts are not solid wastes when reclaimed, unless they are used in a manner constituting disposal; burned for energy recovery, used to produce a fuel, or contained in fuels; or accumulated speculatively (Table 13.1).
These are unused or off-specification chemicals (e.g., chemicals that have exceeded their shelf-life), spill or container residues, and other unused manufactured products that are not typically considered
Regulatory Status of Secondary Materials
These Materials are Solid Wastes When
Used in a Manner Reclaimed Constituting Disposal
Spent materials Listed sludges Characteristic sludges Listed byproducts Characteristic byproducts Commercial chemical products Scrap metal
Burned for Energy Recovery, Used to Produce a Fuel, or Contained in Fuels
Source: U.S. EPA, Resource Conservation and Recovery Act—Orientation Manual, Report EPA 530-R-02-016, U.S. EPA,
Washington, DC, January 2003. a If such management is consistent with the product's normal use, then commercial chemical products used in a manner constituting disposal or burned for energy recovery, used to produce a fuel, or contained in fuels are not solid wastes.
chemicals. Commercial chemical products are not solid wastes when reclaimed, unless they are used in a manner constituting disposal; or burned for energy recovery, used to produce a fuel, or contained in fuels (Table 13.1).
Scrap metal comprises worn or extra bits and pieces of metal parts, such as scrap piping and wire, or worn metal items, such as scrap automobile parts and radiators. If scrap metal is reclaimed, it is a solid waste and is subject to hazardous waste regulation. Scrap metal is also regulated as a solid waste when used in a manner constituting disposal; burned for energy recovery, used to produce a fuel, or contained in fuels; or accumulated speculatively. This does not apply to processed scrap metal, which is excluded from hazardous waste generation entirely.
For all recycling activities, the above rules are based on the premise that legitimate reclamation or reuse is taking place. U.S. EPA rewards facilities recycling some wastes by exempting them from regulation, or by subjecting them to less stringent regulation. Some facilities, however, may claim that they are recycling a material in order to avoid being subject to RCRA regulation, when in fact the activity is not legitimate recycling. U.S. EPA has established guidelines for what constitutes legitimate recycling and has described activities it considers to be illegitimate or sham recycling. Considerations in making this determination include whether the secondary material is effective for the claimed use, if the secondary material is used in excess of the amount necessary, and whether or not the facility has maintained records of the recycling transactions. Sham recycling may include situations when a secondary material falls into the following categories:
1. It is ineffective or only marginally effective for the claimed use (e.g., using certain heavy metal sludges in concrete when such sludges do not contribute any significant element to the concrete's properties).
2. It is used in excess of the amount necessary (e.g., using materials containing chlorine as an ingredient in a process requiring chlorine, but in excess of the required chlorine levels).
3. It is handled in a manner inconsistent with its use as a raw material or commercial product substitute (e.g., storing materials in a leaking surface impoundment as compared to a tank in good condition that is intended for storing raw materials).
Not all RCRA solid wastes qualify as hazardous wastes. Other factors must be considered before deciding whether a solid waste should be regulated as a hazardous waste. Regulation of certain wastes may be impractical or otherwise undesirable, regardless of the hazards that the waste might pose. For instance, household waste can contain dangerous chemicals, such as solvents and pesticides, but subjecting households to the strict RCRA waste management regulations would create a number of practical problems. As a result, Congress and U.S. EPA exempted or excluded certain wastes, such as household wastes, from the hazardous waste definition and regulations. Determining whether or not a waste is excluded or exempted from hazardous waste regulation is the second step in the RCRA hazardous waste identification process. There are five categories of exclusions2:
1. Exclusions from the definition of solid waste
2. Exclusions from the definition of hazardous waste
3. Exclusions for waste generated in raw material, product storage, or manufacturing units
4. Exclusions for laboratory samples and waste treatability studies
5. Exclusions for dredged material regulated under the Marine Protection Research and Sanctuaries Act or the Clean Water Act
If the waste fits one of these categories, it is not regulated as an RCRA hazardous waste, and the hazardous waste requirements do not apply.
A material cannot be a hazardous waste if it does not meet the definition of a solid waste. Thus, wastes that are excluded from the definition of solid waste are not subject to the RCRA Subtitle C hazardous waste regulation. There are 20 exclusions from the definition of solid waste:
1. Domestic sewage and mixtures of domestic sewage. Domestic sewage, or sanitary waste, comes from households, office buildings, factories, and any other place where people live and work. These wastes are carried by sewer to a municipal wastewater treatment plant (called a publicly owned treatment works [POTW]). The treatment of these wastes is regulated under the Clean Water Act (CWA). Mixtures of sanitary wastes and other wastes (including hazardous industrial wastes) that pass through a sewer system to a POTW are also excluded from Subtitle C regulation once they enter the sewer. In certain circumstances, this exclusion may be applied to domestic sewage and mixtures of domestic sewage that pass through a federally owned treatment works (FOTW).
2. Industrial wastewater discharges (point source discharges). Another exclusion from RCRA designed to avoid overlap with CWA regulations applies to point source discharges. Point source discharges are discharges of pollutants (e.g., from a pipe, sewer, or pond) directly into a lake, river, stream, or other water body. CWA regulates such discharges under the National Pollutant Discharge Elimination System (NPDES) permitting program. Under this exclusion from the definition of solid waste, wastewaters that are subject to CWA regulations are exempt from Subtitle C regulation at the point of discharge. Any hazardous waste generation, treatment, or storage prior to the discharge is subject to RCRA regulation. Many industrial facilities that treat wastewater on site utilize this point source discharge exclusion.
3. Irrigation return flows. When farmers irrigate agricultural land, water not absorbed into the ground can flow into reservoirs for reuse. This return flow often picks up pesticide or fertilizer constituents, potentially rendering it hazardous. Because this water may be reused on the fields, it is excluded from the definition of solid waste.
4. Radioactive waste. Radioactive waste is regulated by either the Nuclear Regulatory Commission or the U.S. Department of Energy (DOE) under the Atomic Energy Act (AEA). To avoid duplicative regulation under RCRA and AEA, RCRA excludes certain radioactive materials from the definition of solid waste. However, RCRA excludes only the radioactive components of the waste. If a radioactive waste is mixed with a hazardous waste, the resultant mixture is regulated by both AEA and RCRA as a mixed waste. Similarly, if a facility generates a hazardous waste that is also radioactive, the material is a mixed waste and is subject to regulation under both RCRA and AEA.
5. In situ mining waste. In situ mining of certain minerals may involve the application of solvent solutions directly to a mineral deposit in the ground. The solvent passes through the ground, collecting the mineral as it moves. The mineral and solvent mixtures are then collected in underground wells where the solution is removed. Such solvent-contaminated earth, or any nonrecovered solvent, is excluded from the definition of solid waste when left in place.
6. Pulping liquors. Pulping liquor, also called black liquor, is a corrosive material used to dissolve wood chips for the manufacturing of paper and other materials. To promote waste minimization and recycling, U.S. EPA excluded pulping liquors from the definition of solid waste if they are reclaimed in a recovery furnace and then reused in the pulping process. If the liquors are recycled in another way, or are accumulated speculatively, they are not excluded.
7. Spent sulfuric acid. Spent sulfuric acid may be recycled to produce virgin sulfuric acid. To promote waste reduction and recycling, such recycled spent sulfuric acid is excluded from the definition of solid waste, unless the facility accumulates the material speculatively.
8. Closed-loop recycling. To further promote waste reduction and recycling, spent materials that are reclaimed and returned to the original process in an enclosed system of pipes and tanks are excluded from the definition of solid waste, provided that the following conditions are met:
(a) Only tank storage is involved, and the entire process, through reclamation, is closed to the air (i.e., enclosed).
(b) Reclamation does not involve controlled flame combustion, such as that which occurs in boilers, industrial furnaces, or incinerators.
(c) Waste materials are never accumulated in tanks for more than 12 months without being reclaimed.
(d) Reclaimed materials are not used to produce a fuel, or used to produce products that are used in a manner constituting disposal.
An example of such a closed-loop system might include a closed solvent recovery system in which the dirty solvents are piped from the degreasing unit to a solvent still where the solvent is cleaned, and then piped back to the degreasing unit.
9. Spent wood preservatives. Many wood-preserving plants recycle their wastewaters and spent wood-preserving solutions. These materials are collected on drip pads and sumps, and are in many cases returned directly to the beginning of the wood-preserving process where they are reused in the same manner. Although the process resembles a closed-loop recycling process, the closed-loop recycling exclusion does not apply because drip pads are open to the air. Consistent with their objective to encourage recycling hazardous waste, U.S. EPA developed two specific exclusions for spent wood-preserving solutions and wastewaters containing spent preservatives, provided that the materials have been reclaimed and are reused for their original purpose. In addition, wood-preserving solutions and wastewaters are excluded from the definition of solid waste prior to reclamation. To use this exclusion, a facility is required to reuse the materials for their intended purpose and manage them in a way that prevents releases to the environment.
10. Coke byproduct wastes. Coke, used in the production of iron, is made by heating coal in high-temperature ovens. Throughout the production process many byproducts are created. The refinement of these coke byproducts generates several listed and characteristic wastestreams. However, to promote recycling of these wastes, U.S. EPA provided an exclusion from the definition of solid waste for certain coke byproduct wastes that are recycled into new products.
11. Splash condenser dross residue. The treatment of steel production pollution control sludge generates a zinc-laden residue, called dross. This material, generated from a splash condenser in a high-temperature metal recovery process, is known as a splash condenser dross residue. Because this material contains 50 to 60% zinc, it is often reclaimed, reused, or processed as a valuable recyclable material. Facilities commonly handle this material as a valuable commodity by managing it in a way that is protective of human health and the environment, so U.S. EPA excluded this residue from the definition of solid waste.
12. Hazardous oil-bearing secondary materials and recovered oil from petroleum-refining operations. Petroleum-refining facilities sometimes recover oil from oily wastewaters and reuse this oil in the refining process. In order to encourage waste minimization and recycling, U.S. EPA excluded such recovered oil from the definition of solid waste when it is returned to the refinery. Oil-bearing hazardous wastes that are recycled back into the petroleum-refining process are also excluded. In 2002, U.S. EPA proposed to conditionally exclude oil-bearing secondary materials that are processed in a gasification system to produce synthesis gas fuel and other nonfuel chemical byproducts. Condensates from the Kraft process steam strippers, the most commonly used pulping process today, utilizes various chemicals to break down wood into pulp. This process generates overhead gases that are condensed and often recycled as fuel. To encourage the recycling of these condensates, U.S. EPA excluded them from the definition of solid waste provided the condensate is combusted at the mill that generated it.
13. Comparable fuels. In order to promote the recycling of materials with high fuel values, certain materials that are burned as fuels are excluded from the definition of solid waste, provided that they meet certain specifications (i.e., are of a certain degree of purity). This is to ensure that the material does not exceed certain levels of toxic constituents and physical properties that might impede burning. Materials that meet this specification are considered comparable to pure or virgin fuels.
14. Processed scrap metal. Scrap metal includes, but is not limited to, pipes, containers, equipment, wire, and other metal items that are no longer of use. To facilitate recycling, scrap metal that has been processed to make it easier to handle or transport and is sent for metals recovery is excluded from the definition of solid waste. Unprocessed scrap metal is still eligible for an exemption from hazardous waste regulation when recycled.
15. Shredded circuit boards. Circuit boards are metal boards that hold computer chips, thermostats, batteries, and other electronic components. Circuit boards can be found in computers, televisions, radios, and other electronic equipment. When this equipment is thrown away, these boards can be removed and recycled. Whole circuit boards meet the definition of scrap metal, and are therefore exempt from hazardous waste regulation when recycled. On the other hand, some recycling processes involve shredding the board. Such shredded boards do not meet the exclusion for recycled scrap metal. In order to facilitate the recycling of such materials, U.S. EPA excluded recycled shredded circuit boards from the definition of solid waste, provided that they are stored in containers sufficient to prevent release to the environment, and are free of potentially dangerous components, such as mercury switches, mercury relays, nickel-cadmium batteries, and lithium batteries.
16. Mineral processing spent materials. Mineral processing generates spent materials that may exhibit hazardous waste characteristics. Common industry practice is to recycle these mineral processing wastes back into the processing operations to recover mineral value. U.S. EPA created a conditional exclusion from the definition of solid waste for these spent materials when recycled in the mineral processing industry, provided the materials are stored in certain types of units and are not accumulated speculatively.
17. Petrochemical recovered oil. Organic chemical manufacturing facilities sometimes recover oil from their organic chemical industry operations. U.S. EPA excluded petrochemical recovered oil from the definition of solid waste when the facility inserts the material into the petroleum-refining process of an associated or adjacent petroleum refinery. Only petrochemical recovered oil that is hazardous because it exhibits the characteristic of ignitability or exhibits the toxicity characteristic for benzene (or both) is eligible for the exclusion.
18. Spent caustic solutions from petroleum refining. Petrochemical refineries use caustics to remove acidic compounds such as mercaptans from liquid petroleum streams to reduce produced odor and corrosivity as well as to meet product sulfur specifications. Spent liquid treating caustics from petroleum refineries are excluded from the definition of solid waste if they are used as a feedstock in the manufacture of napthenic and cresylic acid products. U.S. EPA believes that spent caustic, when used in this manner, is a valuable commercial feedstock in the production of these particular products, and is therefore eligible for exclusion.
19. Glass frit and fluoride-rich baghouse dust generated by vitrification. In July 2000, U.S. EPA proposed that glass frit and fluoride-rich baghouse dust generated by vitrification be classified as products and excluded from the definition of solid waste. Glass frit is useable as a commercial chemical product, and fluoride-rich baghouse dust can be recycled back into the aluminum reduction pots as electrolyte or sold as a product for other industrial uses such as steel making.
20. Zinc fertilizers made from recycled hazardous secondary materials. U.S. EPA promulgated a conditional exclusion from the definition of solid waste for hazardous secondary materials that are recycled to make zinc fertilizers or zinc fertilizer ingredients. Zinc, an important micronutrient for plants and animals, can be removed from zinc-rich manufacturing residue and used to produce zinc micronutrient fertilizer. A second conditional exclusion applies to the zinc fertilizer products made from these secondary materials.
U.S. EPA also exempts certain solid wastes from the definition of hazardous waste. If a material meets an exemption from the definition of hazardous waste, it cannot be a hazardous waste, even if the material technically meets a listing or exhibits a characteristic. There are 16 exemptions from the definition of hazardous waste:
1. Household hazardous waste. Households often generate solid wastes that could technically be hazardous wastes (e.g., solvents, paints, pesticides, fertilizer, poisons). However, it would be impossible to regulate every house in the U.S. that occasionally threw away a can of paint thinner or a bottle of rat poison. Therefore, U.S. EPA developed the household waste exemption. Under this exemption, wastes generated by normal household activities (e.g., routine house and yard maintenance) are exempt from the definition of hazardous waste. U.S. EPA has expanded the exemption to include household-like areas, such as bunkhouses, ranger stations, crew quarters, campgrounds, picnic grounds, and day-use recreation areas. Although household hazardous waste is exempt from Subtitle C, it is regulated under Subtitle D as a solid waste.
2. Agricultural waste. To prevent overregulation of farms and promote waste recycling, solid wastes generated by crop or animal farming are excluded from the definition of hazardous waste provided that the wastes are returned to the ground as fertilizers or soil conditioners. Examples of such wastes are crop residues and manures.
3. Mining overburden. After an area of a surface mine has been depleted, it is common practice to return to the mine the earth and rocks (overburden) that were removed to gain access to ore deposits. When the material is returned to the mine site, it is not a hazardous waste under RCRA.
4. Bevill and Bentsen wastes. In the Solid Waste Disposal Act Amendments of 1980, Congress amended RCRA by exempting oil, gas, and geothermal exploration, development, and production wastes (Bentsen wastes); fossil fuel combustion wastes; mining and mineral processing wastes; and cement kiln dust wastes (Bevill wastes) from the definition of hazardous waste pending further study by U.S. EPA. These wastes were temporarily exempted because they were produced in very large volumes, were thought to pose less of a hazard than other wastes, and were generally not amenable to the management practices required under RCRA. Items 5 to 8 (following) describe these exemptions in detail.
5. Fossil fuel combustion waste. In order to accommodate effective study, fossil fuel combustion wastes were divided into two categories, large-volume coal-fired utility wastes and the remaining wastes. After studying these wastes, in 1993 U.S. EPA decided to permanently exempt large-volume coal-fired utility wastes, including fly ash, bottom ash, boiler slag, and flue gas emission control waste from the definition of hazardous waste. Further study by U.S. EPA, in 2000, indicated that all remaining fossil fuel combustion wastes need not be regulated under RCRA Subtitle C. However, U.S. EPA determined that national nonhazardous waste regulations under RCRA Subtitle D are appropriate for coal combustion wastes disposed in surface impoundments and landfills and used as mine-fill. These regulations have now been proposed and subsequently finalized by U.S. EPA.
6. Oil, gas, and geothermal wastes. Certain wastes from the exploration and production of oil, gas, and geothermal energy are excluded from the definition of hazardous waste. These wastes include those that have been brought to the surface during oil and gas exploration and production operations, and other wastes that have come into contact with the oil and gas production stream (e.g., during removal of waters injected into the drill well to cool the drill bit).
7. Mining and mineral processing wastes. Certain wastes from the mining, refining, and processing of ores and minerals are excluded from the definition of hazardous waste.
8. Cement kiln dust. Cement kiln dust is a fine-grained solid byproduct generated during the cement manufacturing process and captured in a facility's air pollution control system. After study, U.S. EPA decided to develop specific regulatory provisions for cement kiln dust. Until U.S. EPA promulgates these new regulatory controls, however, cement kiln dust will generally remain exempt from the definition of hazardous waste.
9. Trivalent chromium wastes. The element chromium exists in two forms, hexavalent and trivalent. U.S. EPA determined that, although hexavalent chromium poses enough of a threat to merit regulation as a characteristic hazardous waste, trivalent chromium does not. Therefore, to prevent unnecessary regulation, U.S. EPA excluded from the definition of hazardous waste trivalent chromium-bearing hazardous wastes from certain leather-tanning, shoe-manufacturing, and leather-manufacturing industries.
10. Arsenically treated wood. Discarded arsenically treated wood or wood products that are hazardous only because they exhibit certain toxic characteristics (e.g., contain harmful concentrations of metal or pesticide constituents), are excluded from the definition of hazardous waste. Once such treated wood is used, it may be disposed of by the user (commercial or residential) without being subject to hazardous waste regulation. This exclusion is based on the fact that the use of such wood products on the land is similar to the common disposal method, which is landfilling. This exclusion applies only to endusers and not to manufacturers.
11. Petroleum-contaminated media and debris from underground storage tanks (USTs). USTs are used to store petroleum (e.g., oil) and hazardous substances (e.g., ammonia). When these tanks leak, the UST program under RCRA Subtitle I provides requirements for cleaning up such spills. To facilitate the corrective action process under the UST regulations, contaminated media (soils and groundwater) and debris (tanks and equipment) at sites undergoing UST cleanup that are hazardous only because they exhibit certain toxic characteristics (e.g., contain a harmful concentrations of leachable organic constituents) are excluded from the definition of hazardous waste.
12. Spent chlorofluorocarbon refrigerants. Chlorofluorocarbons (CFCs) released to the atmosphere damage the stratospheric ozone layer. To promote recycling and discourage the practice of venting used CFCs to the atmosphere as a means of avoiding Subtitle C regulation, U.S. EPA excluded recycled CFCs from the definition of hazardous waste because the refrigerants are generally reclaimed for reuse.
13. Used oil filters. In order to promote the recycling and recovery of metals and other products from used oil filters, U.S. EPA exempted used oil filters that have been properly drained to remove the used oil.
14. Used oil distillation bottoms. When used oil is recycled, residues (called distillation bottoms) form at the bottom of the recycling unit. To promote the recycling of used oil and the beneficial reuse of waste materials, U.S. EPA excluded these residues from the definition of hazardous waste when the bottoms are used as ingredients in asphalt paving and roofing materials.
15. Landfill leachate or gas condensate derived from listed waste. Landfill leachate and landfill gas condensate derived from previously disposed wastes that now meet the listing description of one or more of the petroleum refinery listed wastes would be regulated as a listed hazardous waste. However, U.S. EPA temporarily excluded such landfill leachate and gas condensate from the definition of hazardous waste provided their discharge is regulated under the CWA. The exclusion will remain effective while U.S. EPA studies how the landfill leachate and landfill gas condensate are currently managed, and the effect of future CWA effluent limitation guidelines for landfill wastewaters.
16. Project XL pilot project exclusions. U.S. EPA has provided two facilities with site-specific hazardous waste exclusions pursuant to the Project XL pilot program. The waste generated from the copper metallization process at the IBM Vermont XL project is excluded from the listing. Byproducts resulting from the production of automobile air bag gas generants at the Autoliv ASP Inc. XL project in Utah are also exempt from regulation as hazardous waste. In addition to these finalized exclusions, in July 2001 U.S. EPA proposed a site-specific exclusion for mixed wastes generated at the Ortho-McNeil Pharmaceutical Inc. facility in Spring House, PA, under the Project XL program.
126.96.36.199 Raw Material, Product Storage, and Process Unit Waste Exclusions
Hazardous wastes generated in raw material, product storage, or process (e.g., manufacturing) units are exempt from Subtitle C hazardous waste regulation while the waste remains in such units. These units include tanks, pipelines, vehicles, and vessels used either in the manufacturing process or for storing raw materials or products, but specifically do not include surface impoundments. Once the waste is removed from the unit, or when a unit temporarily or permanently ceases operation for 90 days, the waste is considered generated and is subject to regulation.
Hazardous waste samples are small, discrete amounts of hazardous waste that are essential to ensure accurate characterization and proper hazardous waste treatment. In order to facilitate the analysis of these materials, RCRA exempts characterization samples and treatability study samples from Subtitle C hazardous waste regulation:
1. Waste characterization samples. Samples sent to a laboratory to determine whether or not a waste is hazardous are exempt from regulation. Such samples (typically less than one gallon of waste) are excluded from Subtitle C regulation, provided that these samples are collected and shipped for the sole purpose of determining hazardous waste characteristics or composition. Storage, transportation, and testing of the sample are excluded from RCRA regulation even when the laboratory testing is complete, provided the sample is returned to the generator, and other specific provisions are met. When shipping the sample to or from the laboratory, the sample collector must comply with certain labeling requirements, as well as any applicable U.S. Postal Service (USPS) or U.S. Department of Transportation (DOT) shipping requirements.
2. Treatability study samples. To determine if a particular treatment method will be effective on a given waste or what types of wastes remain after the treatment is complete, facilities send samples of waste to a laboratory for testing. U.S. EPA conditionally exempts those who generate or collect samples for the sole purpose of conducting treatability studies from the hazardous waste regulations, provided that certain requirements, including packaging, labeling, and record-keeping provisions, are met. In addition, under specific conditions, laboratories conducting such treatability studies may also be exempt from Subtitle C regulation.
Dredge materials subject to the permitting requirements of Section 404 of the Federal Water Pollution Control Act of Section 103 of the Marine Protection, Research, and Sanctuaries Act of 1972 are not considered hazardous wastes.
13.4 DEFINITION OF HAZARDOUS WASTE
According to Congress, the original statutory definition of the term hazardous waste is as follows:
A solid waste, or combination of solid waste, which because of its quantity, concentration, or physical, chemical, or infectious characteristics may (a) cause, or significantly contribute to, an increase in mortality or an increase in serious irreversible, or incapacitating reversible, illness; or (b) pose a substantial present or potential hazard to human health or the environment when improperly treated, stored, transported, or disposed of, or otherwise managed.
This broad statutory definition provides a general indication of which wastes Congress intended to regulate as hazardous, but it obviously does not provide the clear distinctions necessary for industrial waste handlers to determine whether their wastes pose a sufficient threat to warrant regulation or not. Congress instructed U.S. EPA to develop more specific criteria for defining hazardous waste. There are therefore two definitions of hazardous waste under the RCRA program: a statutory definition and a regulatory definition. The statutory definition cited above is seldom used today. It served primarily as a general guideline for U.S. EPA to follow in developing the regulatory definition of hazardous waste. The regulatory definition is an essential element of the current RCRA program. It precisely identifies which wastes are subject to RCRA waste management regulations.
Congress asked U.S. EPA to fulfill the task of developing a regulatory definition of hazardous waste by using two different mechanisms: by listing certain specific wastes as hazardous and by identifying characteristics that, when present in a waste, make it hazardous. Following its statutory mandate, U.S. EPA developed a regulatory definition of hazardous waste that incorporates both listings and characteristics. In regulatory terms, a RCRA hazardous waste is a waste that appears on one of the four hazardous wastes lists (F list, K list, P list, or U list), or exhibits at least one of four characteristics—ignitability, corrosivity, reactivity, or toxicity.4
A hazardous waste listing is a narrative description of a specific type of waste that U.S. EPA considers dangerous enough to warrant regulation. Hazardous waste listings describe wastes from various industrial processes, wastes from specific sectors of industry, or wastes in the form of specific chemical formulations. Before developing a hazardous waste listing, U.S. EPA thoroughly studies a particular wastestream and the threat it can pose to human health and the environment. If the waste poses enough of a threat, U.S. EPA includes a precise description of that waste on one of the hazardous waste lists in the regulations. Thereafter, any waste fitting that narrative listing description is considered hazardous, regardless of its chemical composition or any other potential variable. For example, one of the current hazardous waste listings is: "API separator sludge from the petroleum refining industry." An API separator is a device commonly used by the petroleum-refining industry to separate contaminants from refinery wastewaters. After studying the petroleum-refining industry and typical sludges from API separators, U.S. EPA decided these sludges were dangerous enough to warrant regulation as hazardous waste under all circumstances. The listing therefore designates all petroleum-refinery API separator sludges as hazardous. Chemical composition or other factors about a specific sample of API separator sludge are not relevant to its status as hazardous waste under the RCRA program.
Using listings to define hazardous wastes presents certain advantages and disadvantages. One advantage is that listings make the hazardous waste identification process easy for industrial waste handlers. Only knowledge of a waste's origin is needed to determine if it is listed; laboratory analysis is unnecessary. By comparing any waste to narrative listing descriptions, one can easily determine whether or not the waste is hazardous. U.S. EPA's use of listings also presents certain disadvantages. For example, listing a waste as hazardous demands extensive study of that waste by U.S. EPA. U.S. EPA lacks the resources to investigate the countless types of chemical wastes produced in the U.S., and therefore the hazardous waste listings simply cannot address all dangerous wastes. Another disadvantage of the hazardous waste listings is their lack of flexibility. Listings designate a waste as hazardous if it falls within a particular category or class. The actual composition of the waste is not a consideration as long as the waste matches the appropriate listing description. For instance, some API separator sludges from petroleum refining might contain relatively few hazardous constituents and pose a negligible risk to human health and the environment. Such sludges are still regulated as hazardous, however, because the listing for this wastestream does not consider the potential variations in waste composition. Thus, the hazardous waste listings can unnecessarily regulate some wastes that do not pose a significant health threat. It is also possible for industries to substantially change their processes so that wastes would no longer meet a listing description in spite of the presence of hazardous constituents. The hazardous waste characteristics provide an important complement to listings by addressing most of the shortcomings of the listing methodology of hazardous waste identification.
A hazardous waste characteristic is a property that, when present in a waste, indicates that the waste poses a sufficient threat to merit regulation as hazardous. When defining hazardous waste characteristics, U.S. EPA does not study particular wastestreams from specific industries. Instead, U.S. EPA asks the question, "What properties or qualities can a waste have which cause that waste to be dangerous?" For example, U.S. EPA found that ignitability, or the tendency for a waste to easily catch fire and burn, is a dangerous property. Thus, ignitability is one of the hazardous waste characteristics, and a waste displaying that property is regulated as hazardous, regardless of whether the waste is listed. When defining hazardous waste characteristics, U.S. EPA identifies, where practicable, analytical tests capable of detecting or demonstrating the presence of the characteristic. For instance, U.S. EPA regulations reference a laboratory flash-point test to be used when deciding if a liquid waste is ignitable. Whether or not a waste displays a hazardous characteristic generally depends on how it fares in one of the characteristics tests. Therefore, the chemical makeup or other factors about the composition of a particular waste typically determine whether or not it tests as hazardous for a characteristic.
Using characteristics to define hazardous wastes presents certain advantages over designating hazardous wastes by listings. One advantage is that hazardous characteristics and the tests used to evaluate their presence have broad applicability. Once U.S. EPA has defined a characteristic and selected a test for use in identifying it, waste handlers can evaluate any wastestream to see if it is classified as a hazardous waste. Furthermore, use of characteristics can be a more equitable way of designating wastes as hazardous. Instead of categorizing an entire group of wastes as hazardous, characteristics allow a waste handler to evaluate each waste sample on its own merits and classify it according to the actual danger it poses. Aware of these advantages, U.S. EPA originally planned to use characteristics as the primary means of identifying hazardous waste. U.S. EPA hoped to define and select test methods for identifying all hazardous characteristics, including organic toxicity, mutagenicity (the tendency to cause mutations), teratogenicity (the tendency to cause defects in offspring), bioaccumulation potential, and phytotoxicity (toxicity to plants). U.S. EPA encountered problems, however, when trying to develop regulatory definitions of these properties. One primary problem was that no straightforward testing protocols were available for use in determining if a
Typical Hazardous Wastes Generated by Selected Industries
Vehicle maintenance shops
Strong acids and bases Reactive wastes Ignitable wastes
Discarded commercial chemical products
Paint wastes Ignitable wastes Spent solvents Acids and bases
Photography waste with heavy metals Heavy metal solutions Waste inks Spent solvents
Ignitable wastes Corrosive wastes
Ink wastes, including solvents and metals
Ignitable wastes Paint wastes Spent solvents Strong acids and bases
Heavy metal dusts and sludges Ignitable wastes Solvents
Strong acids and bases
Ignitable wastes Spent solvents Paint wastes
Paint wastes containing heavy metals Strong acids and bases Cyanide wastes
Sludges containing heavy metals
Source: U.S. EPA, Hazardous Waste, available at http://www.epa.gov/epaoswer/osw/ hazwaste.htm#hazwaste, 2008.
Cleaning agents and cosmetic manufacturing
Metal manufacturing waste possessed any of these characteristics. For example, deciding if a particular wastestream poses an unacceptable cancer risk demands extensive laboratory experimentation. Requiring such analysis on a routine basis from industrial waste handlers would be impractical. Therefore, U.S. EPA developed a hazardous waste definition that relies on both listings and characteristics to define hazardous wastes. Table 13.2 shows some typical hazardous wastes generated by selected industries.3
U.S. EPA has studied and listed as hazardous hundreds of specific industrial wastestreams. These wastes are described or listed on four different lists that are found in the regulations (RCRA Part 261, Subpart D). These four lists are as follows2:
1. The F list. The F list designates as hazardous particular wastes from certain common industrial or manufacturing processes. Because the processes producing these wastes can occur in different sectors of industry, the F list wastes are known as wastes from nonspecific sources.
2. The K list. The K list designates as hazardous particular wastestreams from certain specific industries. K-list wastes are known as wastes from specific sources.
3. The P list and the U list. These two lists are similar in that both list as hazardous pure or commercial grade formulations of certain specific unused chemicals.
These four lists each designate anywhere from 30 to a few hundred wastestreams as hazardous. Each waste on the lists is assigned a waste code consisting of the letter associated with the list followed by three numbers. For example, the wastes on the F list are assigned the waste codes F001, F002, and so on. These waste codes are an important part of the RCRA regulatory system. Assigning the correct waste code to a waste has important implications for the management standards that apply to the waste.
Before listing any waste as hazardous, U.S. EPA developed a set of criteria to use as a guide when determining whether or not a waste should be listed. These listing criteria provide a consistent frame of reference when U.S. EPA considers listing a wastestream. Remember that U.S. EPA only uses these criteria when evaluating whether to list a waste; the listing criteria are not used by waste handlers, who refer to the actual hazardous waste lists for hazardous waste identification purposes. There are four different criteria upon which U.S. EPA may base its determination to list a waste as hazardous. Note that these four criteria do not directly correspond to the four different lists of hazardous waste. The four criteria U.S. EPA may use to list a waste as follows1:
1. The waste typically contains harmful chemicals, and other factors indicate that it could pose a threat to human health and the environment in the absence of special regulation. Such wastes are known as toxic listed wastes.
2. The waste contains such dangerous chemicals that it could pose a threat to human health and the environment even when properly managed. Such wastes are known as acutely hazardous wastes.
3. The waste typically exhibits one of the four characteristics of hazardous waste described in the hazardous waste identification regulations (ignitability, corrosivity, reactivity, or toxicity).
4. When U.S. EPA has a cause to believe for some other reason, the waste typically fits within the statutory definition of hazardous waste developed by Congress.
U.S. EPA may list a waste as hazardous for any and all of the above reasons. The majority of listed wastes fall into the toxic waste category. To decide if a waste should be a toxic listed waste, U.S. EPA first determines whether it typically contains harmful chemical constituents. An appendix to RCRA contains a list of chemical compounds or elements that scientific studies have shown to have toxic, carcinogenic, mutagenic, or teratogenic effects on humans or other life forms. If a waste contains chemical constituents found on the appendix list, U.S. EPA then evaluates 11 other factors to determine if the wastestream is likely to pose a threat in
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