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IN-DEPTH GUIDANCE. EVERY MONTH.

In the United States, hazardous wastes are subject to regulations mandated by the Resource Conservation and Recovery Act (RCRA). Every month, we provide clear, in-depth guidance on a different aspect of the RCRA regulations. The information presented here is an excerpt from McCoy’s RCRA Unraveled, 2018 Edition.

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Spent Solvents

Because spent solvents were involved in incidences of environmental damage more often than any other waste type, the initial RCRA regulations included five spent solvent listings. [May 19, 1980; 45 FR 33123] The concept is simple: 1) a solvent is used for its solvent properties, 2) it becomes too contaminated to use any more (i.e., it becomes spent), and 3) the spent solvent chemical is identified by name in one of the F001–F005 listing descriptions.

Those initial F001–F005 listings were for spent solvents that resulted from using pure or technical-grade solvents only. Spent solvents resulting from mixtures of the listed solvents were not regulated until January 1986. [December 31, 1985; 50 FR 53315]

A useful guidance document entitled Solvents in the Workplace—How to Determine If They Are Hazardous Waste, June 2016, is available at http://www.epa.gov/sites/production/files/2016-06/documents/solventdeterminationguidance_6_16_2016.pdf. The document includes hyperlinks to various regulations applicable to spent solvents along with pertinent EPA guidance.

Description of the spent solvents

The five spent solvent listings are found in §261.31. Each includes specific solvent chemicals, but all of the listing descriptions read about the same. We start our discussion of these wastes by providing a short description of each of the five listings.

F001

This listing covers spent halogenated solvents used in large-scale industrial degreasing operations. It includes five specific solvent chemicals (carbon tetrachloride, methylene chloride, tetrachloroethylene, 1,1,1-trichloroethane, and trichloroethylene) and one class of compounds [chlorinated fluorocarbons (CFCs)]. CFCs used as refrigerants are not typically subject to the spent solvent listings, because, as refrigerants, they are not being used as solvents. [July 28, 1989; 54 FR 31336] CFCs and hydrochlorofluorocarbons (HCFCs) used in degreasing operations are included in the F001 listing. [RO 13580] Conversely, hydrofluorocarbons (HFCs) would not be considered F001 spent solvents if used for degreasing. [RO 14323] The five specific spent solvent chemicals were listed due to their toxicity [i.e., they have a hazard code of (T)], while CFCs were listed because they may deplete the earth’s stratospheric ozone layer if released.

F002

Spent halogenated solvents used for purposes other than large-scale industrial degreasing operations comprise the F002 listing. Nine specific solvent chemicals (chlorobenzene, o-dichlorobenzene, methylene chloride, tetrachloroethylene, 1,1,1-trichloroethane, 1,1,2-trichloroethane, 1,1,2-trichloro-1,2,2-trifluoroethane, trichloroethylene, and trichlorofluoromethane) are identified in the listing. When they become spent, they are included in the F002 listing. As with F001, these spent solvents were listed due to their toxicity.

Differences between F001 and F002 listings

You will notice that four solvents (methylene chloride, tetrachloroethylene, trichloroethylene, and 1,1,1-trichloroethane) appear in both the F001 and F002 listings. There has been some confusion over which listing is appropriate when one of these solvents becomes spent. EPA stipulated in guidance that the F001 listing applies when one of these solvents has been used in large-scale industrial degreasing operations, such as cold cleaning or vapor degreasing (open top and conveyorized). On the other hand, the F002 listing applies when the solvent has been used for equipment cleaning or smaller scale degreasing operations, such as industrial maintenance and repair. [RO 13469]

F003

The following nonhalogenated solvents, when spent, are F003 listed hazardous wastes: acetone, n-butyl alcohol, cyclohexanone, ethyl acetate, ethyl benzene, ethyl ether, methanol, methyl isobutyl ketone, and xylene. The F003 spent solvent listing has created a great deal of confusion because these nine solvents were listed only because they are ignitable [i.e., they have a hazard code of (I)]. In the past, some parties have asked EPA why it needed to retain the F003 spent solvent listing, suggesting that these wastes would be adequately regulated under the ignitability characteristic. The agency defended the F003 listing on the basis that “these solvents are likely to contain other toxic contaminants. In fact, solvents become spent when they have been contaminated with other materials (e.g., toxic heavy metals or toxic organic compounds) and must be disposed, reprocessed, or reclaimed.” [50 FR 53317] Therefore, EPA believes the F003 listing is necessary.

How nonignitable F003 spent solvents are regulated

Historically, EPA’s position was that a spent solvent did not have to be ignitable to be an F003 waste. If a solid waste met the listing description for F003 in §261.31, it was an F003 spent solvent. Period. Whether or not the F003 spent solvent was ignitable was irrelevant. [RO 11707] This continues to be the position of most states that have not adopted the rule described in the next paragraph.

On May 16, 2001 [66 FR 27266], EPA published a final rule that changed the regulatory status of F003 spent solvents (and other ICR-only listed wastes). The primary focus of this rule was described as follows:

“[U]nder today’s final rules, all wastes listed solely for an ignitability, reactivity and/or corrosivity characteristic (including mixtures, derived-from and as-generated wastes) are excluded once they no longer exhibit a characteristic.” [66 FR 27268]

The final rule removed §261.3(a)(2)(iii), which dealt with mixtures of ICR-only listed wastes, and added a new §261.3(g) that begins:

“(g)(1) A hazardous waste that is listed in subpart D of this part solely because it exhibits one or more characteristics of ignitability as defined under §261.21, corrosivity as defined under §261.22, or reactivity as defined under §261.23 is not a hazardous waste, if the waste no longer exhibits any characteristic of hazardous waste identified in subpart C of this part.”

Hence, at the federal level, wastes meeting the listing description for F003 spent solvents are not F003 wastes if they do not exhibit a characteristic.

F004

Wastes that result from using cresols, cresylic acid, or nitrobenzene for their solvent properties are F004. These wastes were listed due to their toxicity.

F005

Finally, the F005 listing encompasses the following nonhalogenated spent solvents: benzene, carbon disulfide, 2-ethoxyethanol, isobutanol, methyl ethyl ketone, 2-nitropropane, pyridine, and toluene. These spent solvents were listed for both toxicity and ignitability.

Two criteria must be met for F001–F005 listings to apply

For all listed wastes, including the F-wastes, you should be able to read the listing description in the text of the regs and figure out from that language whether you are managing that hazardous waste or not. Unfortunately, the F001–F005 listing descriptions in the regulations do not include all of the necessary information. EPA provided significant clarifying guidance as to what it wanted to cover in these listings in the December 31, 1985 Federal Register [50 FR 53315]; however, this guidance did not get added to the regulatory language. Instead, it is summarized in the following subsections.

The F001–F005 spent solvent codes apply to the specific solvents contained in the listing descriptions only if both of the following criteria are met [December 31, 1985; 50 FR 53316, RO 11384, 14656]:

  1. The solvent was used for its solvent properties (i.e., to solubilize or mobilize other constituents). Specifically, “solubilizing or mobilizing” include degreasing, cleaning, or fabric scouring, and use as carriers, diluents, extractants, or reaction and synthesis media.
  2. The solvent is spent (i.e., the solvent has been used and is no longer fit for use without being regenerated, reclaimed, or otherwise reprocessed).

Although application of these two criteria may seem simple on the surface, it is not. To help clarify the F001–F005 listings, we provide specific examples below of solvent uses that meet both of these criteria.

Manufacturing operations

A solvent, which contains 80% toluene prior to use, is used to wash out ink mixing tubs. What is the regulatory status of the resulting washes and sludges?

Due to its use as a solvent (cleaning), the spent solvent and resulting sludges are F005 wastes. (These wastes may also carry the K086 code.) [RO 11249, 13041, 13605]

Petroleum-based solvents are used to clean oily machine parts. Are the spent solvents (that contain oily residues) regulated as used oil under Part 279?

No. The solvents were used for their solvent properties (degreasing or cleaning), and the residues from cleaning are spent. Therefore, the residues become a solid waste subject to a hazardous waste determination. If the solvent is one of the chemicals specified in the F001–F005 listings, the residues will carry F001–F005 codes. The used oil regulations do not apply. [RO 14396]

Methylene chloride is used as a reaction medium in a manufacturing process. When spent, the medium is removed, stored in containers, reclaimed, and then returned to the production unit. What is the status of the spent medium?

Since it is used as a reaction medium, the methylene chloride has been used for its solvent properties. Consequently, when the spent material exits the production process unit, it becomes a listed F002 spent solvent. [RO 12384] Note that the closed-loop recycling with reclamation exemption [§261.4(a)(8)] is not applicable because the spent medium is stored in containers—not tanks that are hard-piped. Also note that under the federal regulations promulgated on October 30, 2008 and January 13, 2015, the spent methylene chloride solvent would likely not be a solid waste per §261.4(a)(23). However, many states have not adopted these new rules.

A parts washer is mounted on top of a drum of clean solvent. Solvent is drawn up into the washer while it is in use and discharged back into the drum afterward. Eventually, the solvent in the drum becomes too contaminated to clean effectively. At that time, the washer is moved to a new drum, and the spent solvent is sent offsite for reclamation. What is the status of the spent solvent?

In December 1986, EPA indicated that the type of parts washer described above is not a manufacturing process unit. Therefore, the solvent from the parts washer is a spent material as soon as the operator decides that it has become too contaminated for further use. In general, spent materials that will be reclaimed are solid wastes [see Table 1 in §261.2(c)]. If the solvent is one of the chemicals in the F001–F005 listings, it will be a listed hazardous waste when spent. [RO 12790]

EPA changed the federal regulations applicable to spent materials being reclaimed on October 30, 2008 [73 FR 64668] and January 13, 2015 [80 FR 1694]. Under the new rules, spent materials that will be transferred to another person for the purpose of reclamation are not solid wastes if certain conditions specified in §261.4(a)(24) are met. If the spent solvent is excluded from the definition of solid waste under §261.4(a)(24), it cannot be a hazardous waste. In states that have not adopted the new rules, the spent solvent is still solid and potentially hazardous waste. Note that the DC Court of Appeals vacated part of the 2015 DSW rule on July 7, 2017 (API v. EPA, Docket No. 09-1038).

A solvent (50% acetone and 50% methanol, before use) is used to remove water from products in a manufacturing unit. The solvent stream that exits the unit has picked up enough water that it is not ignitable. What is the status of the solvent waste?

Use as a drying agent meets the definition of solvent use because the solvent is used to extract water (i.e., it is an extractant). Under the May 16, 2001 rule discussed above, if the spent solvent does not exhibit a characteristic at the point of generation, it is not F003 hazardous waste. (Note that this is the federal interpretation. In states that have not yet adopted the May 16, 2001 rule, the solvent mixture is an F003 waste, regardless of whether it is ignitable. [RO 11447])

Painting operations

Solvents are often used to solubilize or mobilize during painting operations.

Paint is stripped from aircraft prior to repainting. If the stripping compound used is one of the solvents identified in the F001–F005 listings, what is the regulatory status of the stripped paint waste?

Use as a paint stripper is considered to be use as a solvent because the material is being used to solubilize or mobilize the paint. Thus, the stripped paint waste is F001–F005. [RO 11340, 11787, 12906] Note, however, that if the stripper consists solely of F003 constituents, and the spent stripper does not exhibit a characteristic at the point of generation, it is not F003. [§261.3(g)(1)]

Xylene is used to clean paint spray guns, and the xylene/paint mixture is collected on the water wall of a paint spray booth. What is the status of the resulting sludges skimmed off the paint booth sump?

If the sludges exhibit a characteristic at the point of generation, they are F003 hazardous wastes. The xylene is being used for cleaning (i.e., to solubilize the paint), and the resulting spent solvent waste is regulated. [RO 12925]

What is the regulatory status of paint spray booth air filters containing toluene when they are disposed?

Process wastes containing solvents where the solvent is used as an ingredient in the formulation of a commercial chemical product (in this case, the paint) do not fall within the scope of the spent solvent listings. Additionally, the products themselves do not meet the listings. However, should a spent solvent (i.e., a solvent that can no longer be used for its intended purpose without first being reclaimed) be mixed with the filters, the resultant mixture is a listed hazardous waste pursuant to §261.3(a)(2)(iv). [RO 11513] The filters would also have to be evaluated for the four characteristics.

Laboratory activities

Scintillation fluids or cocktails are used in laboratories to count the amount of radioactivity in samples. Xylene or toluene is used in the cocktail to suspend the radioactive sample so that sampling may occur. When disposed, how are the scintillation vials regulated?

The xylene or toluene in the scintillation fluid is used for its solvent properties to mobilize other constituents in solution and to act as a reaction medium. Therefore, disposed (spent) liquid scintillation vials are F003 wastes (for xylene, assuming they exhibit a characteristic at the point of generation) or F005 wastes (for toluene). [RO 11639, 13258]

Solvents in the F001–F005 listings are often used for analytical and research work in laboratories (e.g., in liquid chromatography, rinsing paraffin off tissue culture slides, in ion-exchange columns, in layer separation, as the final step of organic synthesis). Are the wastes generated from these activities regulated as listed hazardous waste?

If the solvents are used to solubilize or mobilize other constituents, the wastes produced are listed spent solvents. Note that for F003 solvents, the wastes would have to exhibit a characteristic at the point of generation to carry this code. [RO 11249, 12917]

Laboratory quality assurance (QA) standards are sometimes created by dissolving P- and U-listed commercial chemical products in listed solvents (e.g., methanol). What is the regulatory status of excess or expired solutions that are to be disposed?

When a solvent is used to formulate a compound or product, neither the solvent nor the formulated product meets the listing description for spent solvents. The QA standards may be P- or U-listed if the commercial chemical product is on the P- or U-list and is the sole active ingredient in the standard. [RO 11437, 11523]

Miscellaneous

Dry cleaning (fabric scouring) operations generate spent solvents and spent cartridge filters containing perchloroethylene (tetrachloroethylene) or 1,1,2-trichloro-1,2,2-trifluoroethane. Are they F002 when disposed?

Yes. [RO 12201, 12818, 13565] Note that dry cleaning wastes generated from hotels would not be excluded under the household waste exclusion. “Even though generated on premises of a temporary residence (i.e., a hotel), dry cleaning waste is not household waste because the spent solvents from the dry cleaning operations are not similar to wastes typically produced by a consumer in the home.” [RO 13736]

Tetrachloroethylene is used to remove PCBs from an electrical transformer. How is the resulting PCB-contaminated material regulated?

Tetrachloroethylene was used in this situation to remove (i.e., to solubilize or mobilize) PCBs from the transformer. When spent, therefore, it is an F002 spent solvent. (TSCA considerations would also apply to the PCB portion of the waste.) [RO 11470]

Spent solvent listings often do not apply

As noted in the above examples, the F001–F005 listings apply in many situations. However, we have seen people assign these codes to wastes when they really don’t apply. A typical overclassification scenario occurs when a drum of waste material is found in the back of a maintenance shop at a large facility. Plant personnel don’t know what the material is or where it came from, so they have it analyzed at their lab to find out what’s in it. The analysis indicates that it contains methylene chloride. The facility wants to get rid of this stuff, but is concerned it may be a RCRA-regulated waste. The first place methylene chloride shows up in the RCRA waste identification (Part 261) regulations is in the F001 spent solvent listing. So, the facility puts the F001 code on the drum and manifests it offsite to a TSD facility. In other words, the facility declared the waste to be F001. And they might be right….

But EPA’s position is that to really know that a solvent-containing waste is an F001–F005 listed waste, a generator would have to know how the solvent was used. The solvent must have been used to solubilize or mobilize something, and, after it is used for that purpose, it must be spent. As the following subsections demonstrate, there are numerous situations in which the spent solvent codes are not applicable to wastes that contain listed solvent chemicals.

Process wastes and products do not fall under the F001–F005 listings

In the December 31, 1985 spent solvent guidance referenced previously, EPA provided direction as to when the F001–F005 listings would not apply. The agency clearly stated that wastes from processes in which solvents were used as reactants or ingredients in the formulation of commercial chemical products (i.e., nonsolvent uses) are not covered by the listings nor are the products themselves. [50 FR 53316] This guidance has also not made it into the §261.31 listing descriptions.

As a result, wastes that contain solvents that were used in an industrial process as reactants or ingredients are not included within the scope of the spent solvent listings. In addition, these waste streams are not hazardous by virtue of the mixture rule since a spent solvent is not being mixed with another solid waste. [RO 12417] Examples of situations where the F001–F005 waste codes do not apply to process wastes and products are given below.

Solvents used as reactants

When an F001–F005 listed solvent is used as a reactant in a manufacturing process to produce a product, any wastes generated from that process that contain the solvent will not meet the spent solvent listing description. [RO 11384] “The same substances may also be used in a manufacturing process as chemical reactants or process intermediates and, when so used, are not considered to be spent solvents.” [November 17, 1981; 46 FR 56584] Such solvent-containing manufacturing process wastes still may be hazardous if they carry a K-code and/or exhibit a characteristic, but they will not be F001–F005 listed wastes. This concept is illustrated in the following examples.

Listed solvent chemicals (i.e., m-cresol, methanol, and toluene) are used as reactants during pesticide production. For process reasons, the chemicals are used in such excess that large amounts of these materials do not react and are removed from the process as waste streams. What is the regulatory status of these wastes?

Pesticide production wastes that contain the unreacted materials are not listed spent solvents. Use as a feedstock is considered to be a nonsolvent use. Because the solvents are used in significant excess quantities, however, the company was concerned that the solvents could be considered reaction and synthesis media. EPA clarified that a reaction medium “refers to a substance that is capable of dissolving another substance (i.e., the solute) to form a uniformly dispersed mixture or solution thereby enhancing the ability of the solute to undergo a chemical reaction with other soluble substances.” [RO 11079] In this situation, the solvents are reactants—not reaction media.

Toluene is used to convey reactants into a reactor during pesticide production. After the product is formed, the toluene (which is a reaction medium) is separated from the product-bearing stream and returned to the process to convey more reactants. The product-bearing stream is distilled to remove any impurities; the separated impurities are sent offsite for disposal. Is the impurities stream an F005 listed hazardous waste?

No. The toluene that is removed from the product-bearing stream is not spent because it is still in use as a reaction medium. Since it is not F005, the product-bearing stream remaining after the toluene is removed would not be derived from an F005 waste. Finally, the residue remaining after product distillation would be considered a solid waste, but not an F005 hazardous waste or a waste derived from the treatment of an F005 waste. [RO 11703]

Xylene is used as a reactant in the production of sodium xylenesulfonate. Excess xylene from the reactor is separated from the product and distilled before reuse. Are the still bottoms from the recovery of the xylene F003?

No. The xylene is used as a chemical reactant in the production process, and, therefore, the excess xylene stream is not an F003 spent solvent. Hence, the still bottoms generated from the recovery of the xylene are also not spent solvent wastes (although they may exhibit a characteristic). [RO 12809] An almost identical interpretation was rendered by the agency for still bottoms generated during purification of an unreacted toluene stream. [RO 11326]

Solvents used as ingredients

Many commercial products, including paints, inks, and adhesives, contain solvents as ingredients. Formulations of these products may contain a number of the solvents in the F001–F005 listings, such as acetone, methyl ethyl ketone, toluene, and/or xylene. When excess or old paints, inks, and adhesives are thrown out, the F001–F005 listings will not apply per EPA’s guidance. [50 FR 53316, RO 11220, 11340, 11349, 12334, 12906, 13273]

These discarded, unused products containing solvents may still be hazardous, however, if they exhibit a characteristic (e.g., D001). In addition, even though such products will not carry an F001–F005 code, they may be regulated under §261.33 as P- or U-wastes if they contain only one active ingredient and that ingredient is on the P- or U-list. [RO 11787] EPA published similar guidance for waste aerosol cans. Unused solvent residues in non-empty aerosol cans will not be F001–F005 but will be P- or U-listed if the product meets a listing description. [RO 14656]

The F001–F005 listings also do not apply to unused off-specification solvents, which may be regulated under §261.33 as P- or U-wastes. Take, for instance, a company that recycles spent 1,1,1-trichloroethane solvent in a distillation process. After distillation occurs, the recovered solvent may sometimes fail to meet market specifications and, therefore, must be disposed. In this case, the discarded 1,1,1-trichloroethane would be a U226 off-specification commercial chemical product. [RO 12276]

Addition of a solvent to modify a commercial chemical product is also not solvent use that will result in an F-listed spent solvent waste. For example, commercially purchased products (such as paints) to which solvents have been added by the end user to adjust the viscosity (e.g., toluene or xylene added to thin the paint) are not regulated as F001–F005 spent solvents when an unused portion of the modified product is later discarded. [RO 11220, 14005, 14109] “The agency does not recognize a distinction between paints that contain solvents and paint where solvents have been added.” [RO 11249, 12925] However, if spent solvent that meets a listing description (e.g., from cleaning out paint spray apparatus) is mixed with one of the unlisted products to be discarded, the entire mixture would be listed hazardous waste via the mixture rule. Examples where solvents are used as ingredients are given below.

A manufacturer of “pre-coat” uses 2-ethoxyethanol as an ingredient in the process. A waste from the process contains 2-ethoxyethanol—is the waste an F005 spent solvent?

No. Chemicals used as ingredients in the formulation of commercial chemical products are not being used as solvents. The process waste is, therefore, not a listed spent solvent. [RO 11169]

Are activated-carbon canisters used to collect solvent vapors (e.g., Freon 113; 1,1,1-trichloroethane; and methylene chloride), that are generated during the application of paint products, considered to be hazardous wastes?

Since the incorporation of solvents into paint formulations does not constitute solvent use, the solvent vapors collected from paint application are not spent solvents. [RO 11151] The canisters could be hazardous due to a characteristic, however.

During painting operations, a base coat and a top coat are sprayed onto a product. The base coat consists of a resin mixture containing toluene, and the top coat consists of a different toluene-containing resin. In order to clean out the spray gun between coats, the spray gun is directed toward a drum and the top coat is used to clear out base coat or vice versa. Is the waste in the drum a listed spent solvent?

The definition of spent solvent does not extend to cases in which the solvents are strictly reactants or ingredients in a commercial chemical product formulation. “The coating materials merely push the residue of the previous coating out of the nozzle so that pure top or bottom coat can be applied to the products. The toluene is there as part of the manufacturing process itself. It is therefore part of the formulation of the commercial chemical product and not covered by the listing.” [RO 11685, 13585] (Although EPA did not say it in this guidance, we think the waste base or top coat that is contaminated with the other is an off-specification commercial chemical product. Off-spec products are listed only if they contain a sole active ingredient on the P- or U-list. Since the paints will likely not have a sole active ingredient on the P- or U-list, they will only be hazardous via characteristic.) Of course, if pure toluene is used to clean the spray gun, the waste would be considered F005 spent solvent.

A solvent-based product is used as a machining coolant during metal machining, drilling, etc. The coolant contains 80% 1,1,1-trichloroethane and 20% lubricating oil. What is the status of coolant wastes containing this solvent?

The 1,1,1-trichloroethane is being used as an ingredient in product cutting oil—not as a solvent. Assuming that it has not been mixed with a spent solvent, the cutting-oil waste is not an F001 or F002 waste. [RO 11212, 13257]

Other solvent-contaminated process wastes are not F001–F005

EPA has determined that process wastes that become contaminated with small amounts of listed solvents during manufacturing operations are also not within the scope of the spent solvent listings. For instance, rinsewaters that pick up small amounts of solvents during product or equipment rinsing are not considered spent solvents—they are process streams that may have become contaminated with solvents. [RO 11384] In addition, if these solvent-contaminated rinsewaters then contaminate the plant’s process wastewater and wastewater treatment tank sludges, those streams are also not listed spent solvent wastes. [RO 11447]

In general, solvent-contaminated process wastewater exiting manufacturing process units does not meet the spent solvent listing descriptions. Conversely, mixtures of wastewater and listed spent solvents are regulated unless the mixture meets the conditions set forth in the de minimis wastewater exemptions at §261.3(a)(2)(iv)(A) or (B). [RO 11193] Other examples of process wastes that do not carry the F001–F005 listings follow.

Organic liquid-liquid extractions use listed solvents that are nearly immiscible in water (e.g., methylene chloride) to remove an organic product from an aqueous stream. However, the stripped aqueous phase contains small amounts of the solvent that do dissolve into the water. When disposed, is the aqueous stream F002? The solvent is subsequently separated from the product and disposed. What is the regulatory status of the removed solvent?

The aqueous phase from organic liquid-liquid extractions is analogous to a process stream that has become minimally contaminated with solvent constituents (i.e., there was no intentional mixing of a water stream with a spent solvent stream). Therefore, it is not a regulated spent solvent and would be hazardous only if it is a K-listed manufacturing process waste or if it exhibits a characteristic. Conversely, the organic solvents separated from the product were used as extractants (which constitutes solvent use) and, if spent, are listed F001–F005 spent solvents. [RO 11384, 11437, 12658]

Acetone, ethyl acetate, and xylene solvents are periodically used to clean out a reactor vessel. The spent solvents generated during cleanout are drummed and sent offsite for management as F003 wastes. However, trace amounts of solvent remain on the walls of the vessel. This coating is washed off with soap and water. How is this reactor vessel rinsewater regulated?

In this situation, EPA has determined that the resulting solvent-contaminated rinsewater is not covered by the F003 listing. It is generated from the washout of a reactor vessel containing solvent residues. Therefore, the waste is not a spent solvent, but a process wastewater contaminated with solvent constituents. “This waste is very different from a solvent stream that has been used and as a result of contamination can no longer be used as a solvent without further processing.” [RO 11300; see also RO 11384, 11447]

Metal parts are degreased using an F001-listed solvent. The degreased parts are then blasted and ground before finishing; the blasting and grinding grit contains small amounts of solvent residue. Is the grit also F001? What about rinsewater that contains carried-over solvent (dragout) from a metal degreasing operation; would it be hazardous due to the mixture rule?

Small amounts of solvent carried over on parts after cleaning/degreasing are not considered spent and, therefore, do not meet the spent solvent listing description. Therefore, neither the blasting grit nor the spent rinsewater would be F001. (Either of these two wastes could be hazardous via characteristic.) However, if more solvent than necessary is used during cleaning (i.e., it looks like the facility is trying to get rid of its spent solvent by excessive dragout on the metal parts), the excess solvent residues could be considered spent solvent wastes on a case-by-case basis. [RO 11440, 11638, 12896, 13007, 13149]

During production of insulating and packaging foam, CFCs or methylene chloride are used as blowing agents to physically open the foam cells. Once they serve this function, the CFCs or methylene chloride are released and subsequently captured by a vapor-recovery system. Spent CFCs or methylene chloride so captured are shipped offsite for recycling or disposal. What is their regulatory status?

The CFCs or methylene chloride are not being used to solubilize or mobilize. Instead, they are being used to physically open the foam cell. Consequently, use of CFCs or methylene chloride as a blowing agent does not constitute use as a solvent, and the spent solvent listings would not apply. [RO 11494, 13322, 14323]

Toluene is used as a carrier to transport a pharmaceutical product through a number of filtering stages. During the first stage of filtering, an iron impurity is filtered out. What is the regulatory status of the resulting iron-bearing filter cake when disposed? What is the status of the toluene that exits the last stage of filtering after the product has been removed?

Toluene in the stream is being used for its solvent properties (i.e., to solubilize and mobilize the product). However, at the first stage of filtering, the toluene is not spent. Therefore, the iron-bearing cake is neither a residue from the treatment of a spent solvent nor a mixture of a solid waste and a spent solvent. Instead, it is a process waste that is contaminated with a small amount of toluene—not F005. [RO 11311, 13060] Toluene that remains after the product has been separated from it would meet the definition of F005 spent solvent if disposed. [RO 11384]


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Considerable care has been exercised in preparing this document; however, McCoy and Associates, Inc. makes no representation, warranty, or guarantee in connection with the publication of this information. McCoy and Associates, Inc. expressly disclaims any liability or responsibility for loss or damage resulting from its use or for the violation of any federal, state, or municipal law or regulation with which this information may conflict. McCoy and Associates, Inc. does not undertake any duty to ensure the continued accuracy of this information.

This document addresses issues of a general nature related to the federal RCRA regulations. Persons evaluating specific circumstances dealing with the RCRA regulations should review state and local laws and regulations, which may be more stringent than federal requirements. In addition, the assistance of a qualified professional should be enlisted to address any site-specific circumstances.