RO 13570 

PPC 9441.1992(36) 

REGULATORY REQUIREMENTS PERTAINING TO THE MANAGEMENT OF 

WASTE SOLVENTS AND USED OIL 

 

United States Environmental Protection Agency 

Washington, D.C. 20460 

Office of Solid Waste and Emergency Response 

October 28, 1992 

Mr. Basil G. Constantelos, Director 

Environmental Affairs 

Safety-Kleen 

777 Big Timber Road 

Elgin, Illinois 60123 

Dear Mr. Constantelos: 

 Thank you for your letter of May 22, 1992 requesting 

clarification on the regulatory requirements pertaining to the 

management of waste solvents and used oil. We understand you desire 

to provide your customers with a clear interpretation of the 

federal regulations governing the mixing of hazardous waste 

solvents into used oils. Of course, as you know, state regulations 

can be more stringent and broader in scope than the federal 

program. The enclosures to this letter individually address your 

series of questions regarding characterization requirements, waste 

minimization definitions, and the regulatory status of mixtures of 

waste solvents and used oil. Our responses reflect only EPA's 

federal regulations, and not individual state regulatory 

provisions. 

 Thank you for your interest in the safe and effective 

management of used oil. If you have any further questions, please 

contact Michael Petruska of my staff at (202) 260-9888. 

Sincerely, 

Sylvia K. Lowrance, Director 

Office of Solid Waste 

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Enclosures 

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I. Questions on Waste Characterization Requirements 

Question #1: What degree of testing, or burden of 

 proof with respect to knowledge of 

 the waste is needed to ensure that 

 waste mineral spirits is not a 

 hazardous waste? 

Persons who generate solid waste are not specifically required to 

test their wastes to determine whether it exhibits any of the 

hazardous waste characteristics. Instead solid waste generators are 

required to make a determination as to whether or not their wastes 

are hazardous (40 CFR 262.11). This determination may be made 

either by testing the waste or by applying knowledge of the 

characteristics of the waste, in light of the materials or the 

processes used in its generation. If a waste is determined to be 

hazardous, the generator must keep records establishing the basis 

for that determination (40 CFR 262.40(c)). These records must be 

maintained for at least three years from the date that the waste 

was last sent to on-site or off-site treatment, storage, or 

disposal. 

Question #3: If the waste solvent exhibits the 

 characteristic of ignitability, must 

 a generator also test his waste for 

 the TCLP characteristic in order to 

 comply with the land ban 

 restrictions? 

If the waste solvent exhibits the characteristic of ignitability, 

the generator must determine whether the waste exhibits any of the 

other characteristics of hazardous waste identified in Subpart C of 

40 CFR Part 261. This is the case because the generator must 

determine each EPA hazardous waste number (waste code) applicable 

to the waste in order to comply with the land disposal restrictions 

(40 CFR 268.9(a)). In addition, you may be aware of the recent D.C. 

Circuit opinion concerning the "Third Third" land disposal 

restrictions regulations. While there are no obvious implications 

of that decision for the scenario you have described here, we have 

not concluded our analysis of the case, so it is possible there 

could be some implications for your situation. 

Question # 4: Can a generator rely on an analysis 
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 of his unused mineral spirits (e.g., 

 for ignitability and TC 

 characteristics) plus knowledge of 

 his operations to conclude that the 

 resulting waste solvent will not 

 exhibit any hazardous 

 characteristic? 

A generator can rely on analysis of unused mineral spirits plus 

knowledge of the operation to determine whether or not the 

resulting waste solvent exhibits any hazardous characteristic 

provided that he/she has sufficient information to make an accurate 

determination. Persons who generate solid waste are not 

specifically required to test their wastes to determine whether it 

exhibits any of the hazardous waste characteristics. Instead solid 

waste generators are required to make a determination as to whether 

or not their wastes are hazardous (40 CFR 262.11). This 

determination may be made either by testing the waste or by 

applying knowledge of the characteristics of the waste, in light of 

the materials or the processes used in its generation. 

Question #5: If a generator can rely on an 

 analysis of his unused mineral 

 spirits, and knowledge of his 

 operations to conclude that his 

 waste solvent is not hazardous, can 

 Safety-Kleen, as a transporter, 

 storer, and recycler rely on the 

 generator's certification? 

Transporters, storers and recyclers who use knowledge or 

information supplied by others are still responsible for the 

accuracy of the determination. If transporters accept a waste, 

e.g., mineral spirits, that is sometimes hazardous, the 

transporters should discuss with either generator whether their 

particular wastestream is or isn't hazardous. In some cases, 

analysis may be appropriate to help make this determination. 

Question #6: If the waste mineral spirits 

 contains a listed hazardous waste 

 (e.g., waste brake cleaner or some 

 other chlorinated solvent), and the 

 mineral spirits/listed waste mixture 

 is blended into used oil, is the 
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 entire mixture defined as a listed 

 hazardous waste? 

If the entire mineral spirits/listed waste mixture is blended into 

used oil, the entire mixture is subject to regulation as a 

hazardous waste under 40 CFR Parts 260 through 266, 268, 270, and 

124 rather than as a used oil (see 40 CFR 261.3(a)(2)(iv), and the 

new 40 CFR 279.10(b)(1)(i)). 

II. Questions on Waste Minimization 

Question #7: Is the practice of diluting a 

 characteristically hazardous waste 

 into used oil to render the mixture 

 nonhazardous considered waste 

 minimization on a hazardous waste 

 manifest, may generators use this 

 practice as waste minimization in 

 their annual reports, and is it 

 considered waste minimization with 

 respect to the SARA Title III and 

 Pollution Prevention Control Act 

 requirements? 

Waste minimization, as defined by HSWA, means (1) reduction of the 

total volume or quantity of hazardous waste; (2) reduction in the 

toxicity of hazardous waste; or (3) both, as long as the reduction 

is consistent with the goal of minimizing present and future 

threats to human health and the environment. Source reduction is 

the reduction or elimination of hazardous waste at the source, 

usually within a process. Recycling is the use or reuse of waste as 

an effective substitute for a commercial product, or as an 

ingredient or feedstock in an industrial process (1991 National 

Biennial RCRA Hazardous Waste Report). This type of dilution does 

not reduce volume and does not appear to reduce the amount of toxic 

constituents in the mixture. 

III. Questions on the Regulatory Status of Mixtures of Waste 

 Solvents and Used Oil 

Question #8: If a generator mixes its 

 characteristic hazardous waste into 

 its used oil, and the resulting 

 mixture continues to exhibit a 
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 hazardous waste characteristic, is 

 the resulting mixture regulated as a 

 hazardous waste or as a used oil? 

 [Note: does the answer to this 

 question depend on the 

 characteristic exhibited by the 

 solvent and the oil. For example, if 

 the solvent is hazardous due to 

 ignitability, and the mixture is 

 hazardous only for lead.] 

If a generator mixes characteristic hazardous waste into used oil 

and the resultant mixture exhibits a hazardous waste 

characteristic, the resultant mixture is subject to regulation as 

hazardous waste under 40 CFR Parts 260 through 266, 268, 270 and 

124 rather than as a used oil (40 CFR 261.3(a)(2)(iii)). When the 

new Part 279 used oil management standards become effective 

mixtures of used oil and waste which is hazardous solely because it 

exhibits the characteristic of ignitability will be subject to 

regulation as used oil provided that the resultant mixture does not 

exhibit the characteristic of ignitability (40 CFR 

279.10(b)(2)(iii)). 

Question #9: If the mixture is regulated as a 

 hazardous waste, and is destined to 

 be burned for energy recovery, is it 

 regulated in accordance with 40 CFR 

 Part 266 Subpart H? 

If the used oil/solvent mixture is regulated as a hazardous waste, 

and is destined to be burned for energy recovery, it must be 

managed in accordance with the requirements in 40 CFR Part 266 

Subpart H. 

Question #10: If the mixture is regulated as a 

 used oil, is it subject to the used 

 oil exclusion in 40 CFR 

 261.6(a)(2)(iii)? That is, if the 

 mixture is destined to be burned for 

 energy recovery it is excluded from 

 most of the RCRA regulations and 

 managed in accordance with 40 CFR 

 Part 266 Subpart E? 
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If the used oil/solvent mixture is subject to regulation as used 

oil, and is destined to be burned for energy recovery, it must be 

managed in accordance with 40 CFR Part 266 Subpart E. When the new 

Part 279 standards become effective, 40 CFR Part 261.6(a)(4) will 

indicate that mixtures which are regulated as used oil and recycled 

(destined for energy recovery as well as recycled in some other 

manner) are subject to Part 279 rather than Parts 260 through 268. 

The new Part 279 standards will replace 40 CFR Part 266 Subpart E. 

Question #11: If the mixture is regulated as a 

 used oil, is it also subject to the 

 used oil exclusion in 

 261.6(a)(3)(iii)? That is, if the 

 mixture is destined to be recycled 

 in some manner other than burning 

 for energy recovery is it 

 essentially excluded from regulation 

 under RCRA? 

If the used oil/solvent mixture is subject to regulation as used 

oil, and is destined to be recycled in some manner other than 

burning for energy recovery, it is not subject to regulation under 

Parts 262 through Parts 266 or Parts 268, 270, or 124 and is not 

subject to the notification requirements of Section 3010 of RCRA. 

When the new Part 279 standards become effective, 40 CFR Part 

261.6(a)(4) will exclude mixtures which are regulated as used oil 

and recycled (destined for energy recovery as well as recycled in 

some manner other than burning for energy recovery) from the 

requirements of Parts 260 through 268. Rather, such recycled used 

oil mixtures will be subject to the requirements of Part 279. 

Question #12: Is the resulting mixture regulated 

 as a hazardous waste or as a used 

 oil? 

If the resultant used oil/solvent mixture no longer exhibits a 

hazardous characteristic, it is subject to regulation as a used oil 

(40 CFR Part 261.3(a)(2)(iii)). 

Question #13: If the resulting mixture is 

 regulated as a used oil, is it 

 subject to the used oil exclusions 

 included in 40 CFR 261.6(a)(2)(iii) 

 and 261.6(a)(3)(iii)? 
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If the resultant mixture is subject to regulation as used oil and 

the used oil is destined for energy recovery or recycled in some 

manner other than burning for energy recovery, the used oil mixture 

is eligible for the exclusions in 40 CFR 261.6(a)(2)(iii) and 

261.6(a)(3)(iii). When the new Part 279 standards become effective, 

40 CFR Part 261.6(a)(4) will exclude used oil that is recycled 

(destined for energy recovery as well as recycled in some manner 

other than burning for energy recovery) and is also a hazardous 

waste solely because it exhibits a hazardous characteristic from 

the requirements of Parts 260 through 268 and such used oil will 

instead be subject to the requirements of Part 279. 

Question #14: If a generator mixes her 

 characteristic hazardous waste with 

 used oil to generate a nonhazardous 

 mixture destined for recycling, does 

 this constitute treatment? (It may 

 be assumed that this activity is 

 taking place in a 90-day 

 accumulation tank.) 

The mixing of characteristic hazardous waste with used oil in an 

accumulation tank does constitute treatment if the purpose of the 

mixing is to make the waste more amenable for recovery (e.g., 

energy recovery), and/or to make the waste less hazardous (i.e., to 

remove the solvent's ignitable characteristic) (40 CFR 260.10) 

Question #15: If the practice of mixing hazardous 

 waste mineral spirits with used oil 

 is considered treatment, is this 

 type of treatment regulated under 

 RCRA? That is, are generators 

 allowed to treat their hazardous 

 wastes on-site without a permit? 

If the hazardous waste mineral spirits are mixed in the same 

accumulation tank (or container), the tank is regulated both as a 

hazardous waste tank under 40 CFR Section 262.34 and as a used oil 

tank when the new Part 279 standards become effective. Regardless 

of whether the resultant mixture is used oil or hazardous waste, 

both sets of standards apply. EPA does not require a permit to 

treat hazardous waste in an accumulation tank, provided the 

generator meets the requirements of Sections 262.34 and 
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268.7(a)(4), as well as Part 279, Subpart C, when it becomes 

effective. 

Question #16: If generators are allowed to treat 

 their hazardous wastes on-site 

 without a permit, what burden of 

 proof must the generator have to 

 ensure that the resulting mixture is 

 no longer a hazardous waste? Is 

 analysis required to ensure that the 

 characteristically hazardous waste 

 has been treated such that it no 

 longer exhibits the characteristic? 

Regardless of whether or not hazardous waste is being treated onsite without a permit, generators are required to make a 

determination as to whether or not their wastes are hazardous (40 

CFR 262.11). This determination may be made either by testing the 

waste or by applying knowledge of the characteristics of the waste, 

in light of the materials or the processes used in its generation. 

Question #17: Does the treatment of mineral 

 spirits exhibiting a hazardous waste 

 characteristic in used oil to render 

 the mineral spirits nonhazardous 

 constitute dilution? If so, is this 

 practice prohibited under 40 CFR 

 268.3? 

The treatment standard for nonwastewater ignitable wastes 

containing greater than or equal to 10 percent total organic carbon 

is fuel substitution, recovery of organics, or incineration (40 CFR 

268.42 Table 2). Mixing mineral spirits exhibiting a hazardous 

waste characteristic with used oil that will ultimately be treated 

by the specified treatment technology is aggregation of like 

wastestreams and therefore not impermissible dilution (55 FR 

22532). As mentioned in our answer to Question 3, there was a new 

D.C. Circuit opinion on the Third Third regulations, and while we 

saw no obvious connection to your question here, we have not fully 

concluded our analysis of that case, so we cannot be completely 

definitive at this time.