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EPA Asks About Alternatives to TCLP Testing: What the LEAF Methods Mean for Your Hazardous Waste Determinations

EPA's September 2026 notice asks whether LEAF leaching methods could support an alternative to TCLP testing for industrial landfill waste. Nothing changes yet.

by iSi Environmental

A Federal Register document carrying a November 13, 2026 date is easy to mistake for a compliance milestone. It is a Notice, and it imposes no obligation on anyone. On September 14, 2026 EPA published a Request for Information on SW-846 test methods, waste sampling, and Toxicity Characteristic Leaching Procedure testing at 91 FR 58117, docket EPA-HQ-OLEM-2026-7360. The DATES section reads: “Comments and information must be received on or before November 13, 2026 to allow for consideration in any short-term updates to the methods.” (EPA’s own web summary of the RFI gives the date as November 14. The notice and the Federal Register metadata both say November 13.)

Nothing a generator does changes because of this document. No regulatory level moved, no waste code was added or removed, no new form or sampling frequency appeared, and a facility that reads the RFI and changes nothing is in full compliance. 40 CFR 261.24 still makes a solid waste hazardous when a Method 1311 extract contains any of 40 listed contaminants at or above its regulatory level, and Method 1311 remains the only test that decides the toxicity characteristic.

The mechanism matters. TCLP extracts the sample in acetic acid buffered to pH 4.93 at a 20:1 liquid-to-solid ratio, rotated for 18 hours, because the method was built to simulate co-disposal with decomposing municipal refuse, where organic acids drive metal mobility. A lined industrial monofill is a different chemical environment. EPA writes that it is “considering providing a regulatory alternative to TCLP testing for wastes to evaluate leaching of chemicals from wastes disposed in lined landfills other than municipal solid waste landfills,” and asks generators whether they produce or manage a toxicity characteristic hazardous waste stream that “potentially would not exceed leaching-based RCRA regulatory thresholds under management conditions at a non-MSW landfill.”

This post covers the test method and whether it is changing. Two companion posts cover adjacent ground: hazardous waste determination requirements under RCRA is about the duty to determine under 40 CFR 262.11, and RCRA on the job site applies the D008 lead level of 5.0 mg/L to debris.

What is the LEAF method?

LEAF is four EPA SW-846 methods, 1313, 1314, 1315 and 1316, added in Update VI Phase III in May 2019. Method 1313 runs nine or ten parallel extractions across pH 2 to 13. Method 1316 runs five extractions at liquid-to-solid ratios of 10, 5.0, 2.0, 1.0 and 0.5 mL/g-dry. Method 1314 is an up-flow percolation column run to L/S 10, and Method 1315 measures mass transfer from monoliths. EPA states the framework is “voluntary and not a requirement under RCRA” (LEAF How-To Guide).

The difference from TCLP is the output. TCLP gives one number under one set of conditions. LEAF produces a response surface, which EPA’s How-To Guide describes as testing “over a range of values for release-controlling factors.”

Two limits matter. LEAF entered SW-846 as guidance rather than as validated mandatory methods, and EPA states it “intends all of the Update VI methods to be used as guidance” (SW-846 Update VI Announcements). The RFI also states that “the published LEAF methods have only been validated for inorganic chemicals,” with research on organic constituents still underway (91 FR 58117).

What are the TCLP regulatory limits?

40 CFR 261.24 Table 1 lists 40 contaminants under waste codes D004 through D043. Metals run from mercury (D009) at 0.2 mg/L to barium (D005) at 100.0 mg/L, with lead, arsenic, chromium and silver all set at 5.0 mg/L. Organics run from heptachlor and its epoxide (D031) at 0.008 mg/L to 2,4,5-trichlorophenol (D041) at 400.0 mg/L. Meet or exceed any level in a Method 1311 extract and the waste carries that code.

Representative levels (full table at the eCFR link above):

CodeContaminantRegulatory level (mg/L)
D008Lead5.0
D009Mercury0.2
D018Benzene0.5
D031Heptachlor and its epoxide0.008
D043Vinyl chloride0.2

The organics in that table set the ceiling on any LEAF conversation. Thirty-two of the 40 contaminants are organic compounds, including benzene, TCE, PCE, vinyl chloride and the chlorinated pesticides, and LEAF is validated for inorganic constituents only. For those 32 codes it is not an alternative to TCLP at any price.

How does the TCLP test actually work?

Method 1311, Revision 0, July 1992, is a single batch extraction. The sample is reduced to 1 cm or less in its narrowest dimension, then combined with acetic-acid extraction fluid at a 20:1 liquid-to-solid ratio and rotated end-over-end at 30 plus or minus 2 rpm for 18 plus or minus 2 hours. Extraction Fluid #1 is buffered to pH 4.93 plus or minus 0.05. Fluid #2 is unbuffered at pH 2.88 plus or minus 0.05 (Method 1311, full text).

One sentence in the SW-846 compendium carries the entire compliance story: “Most methods are intended as guidance, with the exception of method defined parameters (MDPs) that are mandated by the RCRA regulations” (SW-846 Compendium). Method 1311 is a Method-Defined Parameter, and EPA states MDPs “may not be modified when used for Resource Conservation and Recovery Act (RCRA) testing” (EPA Method 1311 page). The 18 hours, the rpm, the pH and the ratio are the regulation itself.

TCLP also reaches past waste identification. 40 CFR 268.40(b) requires Method 1311 wherever a Land Disposal Restrictions treatment standard is expressed as “mg/L TCLP,” so one extraction often satisfies two programs.

Is EPA replacing the TCLP with LEAF?

No. The September 14, 2026 document at 91 FR 58117 is a Notice, and EPA says it will use the responses “to inform what action, if any, it may take.” What EPA describes considering is narrower than replacement: “a regulatory alternative to TCLP testing” for waste “disposed in lined landfills other than municipal solid waste landfills.” Any actual change would take a separate proposed rule with its own comment period.

“What action, if any” is the operative phrase. EPA has committed to no rulemaking, and the notice says it is “solely for information, research and planning purposes.”

Then there is the delegation lag. RCRA is delegated, with 49 states plus DC and Guam holding authorized base programs that “must be at least as stringent as the federal requirements” while remaining free to adopt more stringent ones (EPA RCRA state authorization). An authorized state’s rules govern its generators until that state adopts the federal revision. A federal alternative your state does not adopt changes nothing at your plant.

When is the comment deadline for EPA’s TCLP request for information?

November 13, 2026. The DATES section of 91 FR 58117 reads: “Comments and information must be received on or before November 13, 2026 to allow for consideration in any short-term updates to the methods.” Comments go to docket EPA-HQ-OLEM-2026-7360 through Regulations.gov. Commenting is voluntary and the date binds no one.

EPA’s own RFI landing page summarizes the close as November 14, while the Federal Register notice and its metadata field both give November 13. When an agency web page and the notice disagree, the notice is the document with legal effect. Build your internal calendar on November 13.

Do I have to do anything before November 13, 2026?

No. A Request for Information imposes no requirement on any regulated party. Your duties are exactly what they were on September 13: make the determination at the point of generation under 40 CFR 262.11, test by Method 1311 where knowledge is inadequate under 262.11(d)(2), assign every applicable waste code under 262.11(g), and keep determination records for three years under 262.11(f).

The one thing November 13 closes is your chance to put operating data into docket EPA-HQ-OLEM-2026-7360 while it can still shape “any short-term updates to the methods.” Nothing anyone does on November 14, 2026 differs from what they did on November 12.

Can I use LEAF instead of TCLP for a hazardous waste determination?

No. EPA states the LEAF methods “do not replace and cannot be directly substituted for required test methods under Resource Conservation and Recovery Act, such as the Toxicity Characteristic Leaching Procedure (TCLP, Method 1311)” (Frequent Questions about the LEAF Methods). Method 1311 is a Method-Defined Parameter that may not be modified for RCRA testing, and LEAF carries no regulatory thresholds. There is no LEAF analogue to the 261.24 table.

A LEAF data set shows how a material releases constituents across pH and liquid-to-solid ratio. It does not tell you whether the waste is D008, because no regulation assigns a waste code to a point on that curve. Run LEAF today and you get engineering data and zero regulatory determinations.

EPA’s How-To Guide lists the intended uses as “beneficial use, disposal, treatment and remediation applications.” The stated non-uses are determining RCRA hazardous waste status, meeting LDR requirements, and replacing required compliance testing.

Cost works against adoption. Method 1313 requires nine or ten parallel extractions and 1316 requires five where Method 1311 requires one, so the analytical load multiplies before anyone interprets a curve. EPA asks commenters what impact “the cost of LEAF testing, relative to TCLP,” would have on their likelihood of adopting it.

What is the penalty for an incorrect hazardous waste determination?

RCRA section 3008(a)(3) carries up to $124,426 per day per violation, and 3008(g) up to $93,058 per day (42 U.S.C. 6928; 40 CFR 19.4). Those are the January 8, 2025 inflation-adjusted levels set by 90 FR 1375 carried into 2026 unchanged. No later EPA part 19 adjustment has published as of September 28, 2026, so anyone telling you penalties went up this year is reading the wrong table.

Real-world exposure is an order of magnitude lower. EPA’s Office of Inspector General, in Report 26-E-0025 (April 28, 2026), found the median RCRA penalty from large quantity generator inspections from 2020 through 2024 was $13,000, at $11,999 for state-led inspections and $18,750 for EPA-led. Of 5,156 enforcement actions in that period, 861 were formal and 535 carried a penalty at all.

The expensive part of a bad determination is rarely the fine. It is the resampling, the re-manifesting of past shipments, the disposal-cost differential once the waste carries the right code, and the written procedure EPA builds into the settlement. In the United Parcel Service RCRA settlement (June 16, 2021, $3.8 million, 183 facilities in five states including Oklahoma and Texas), determination failure was not charged as a standalone count, and the injunctive relief still required standardized hazardous waste determination procedures across every facility.

Can I use generator knowledge instead of TCLP testing?

Within limits. 40 CFR 262.11(d)(1) lets you “apply knowledge of the hazard characteristic of the waste in light of the materials or the processes used to generate the waste.” Subsection (d)(2) requires testing “when available knowledge is inadequate to make an accurate determination,” and (f) requires records supporting the determination for three years.

A methods debate does not enlarge the knowledge option, and some states narrow it. Nebraska DEE publication 05-176 names four streams where knowledge is not sufficient because the wastes are “quite variable in nature”: spent parts washer solvent, spent antifreeze, sump and pit sludges, and spent sorbents. For antifreeze and parts washer solvent, NDEE specifies flash point testing plus TCLP for 8 metals and 10 volatile organics (NDEE 05-176).

Which waste types does EPA say the TCLP handles poorly?

EPA names three in the notice: “TCLP can underestimate leaching of contaminants from some highly alkaline wastes” and “from oily wastes and some paint wastes.” The notice adds that the method does not account for oxidation and reduction reactions, may underestimate chelation-facilitated mobility, and may not predict long-term organic mobility in some treated wastes. EPA’s own Science Advisory Board reviewed TCLP in 1991 and again in 1999 and recommended a more flexible method that could estimate leaching under a broader range of conditions.

EPA published that sequence about its own mandatory method. It finalized TCLP in 1990, its science advisors in 1991 and 1999 questioned its use for estimating leaching under conditions substantially different from those built into the test, and in 2026 it is still the only test that determines the toxicity characteristic. EPA is now asking industry whether to keep it that way.

The operational payoff is narrow. If your stream is highly alkaline, oily or paint-derived, a passing TCLP is the weakest kind of pass, and you should know that before you build a waste profile on one extraction. EPA’s list of defects is specific rather than general, and for a homogeneous granular inorganic waste headed to a lined cell EPA does not claim Method 1311 is broken. It is a single-scenario approximation with known failure modes on named waste types.

Do Kansas, Oklahoma, Texas, Missouri, Nebraska or Colorado have different waste characterization rules?

All six run EPA-authorized RCRA programs that may be more stringent than the federal baseline. Texas already uses a leach test other than TCLP: Class 3 nonhazardous industrial waste is classified by the Seven-Day Distilled Water Leachate Test at 30 TAC 335.521(d) Appendix 4, required by 30 TAC 335.507(4)(A), while Class 1 industrial waste uses TCLP under 30 TAC 335.505(1) (TCEQ waste determination and classification guidance).

Distilled water for seven days is a different leaching premise from acetic acid for 18 hours, and a delegated state has classified waste on it for years. A multi-state generator may already run both tests on the same material for two different purposes.

Kansas adds a laboratory layer rather than a method layer. KDHE guidance directs generators to use process knowledge or to have the waste analyzed at a KDHE-certified laboratory, and to have contractors use a KDHE-certified laboratory for all analytical testing behind a waste profile (KDHE, Hazardous Waste Determinations and Documentation). Missouri adds state generator registration separate from the federal EPA ID, with annual fees of $500 for LQGs and $150 for SQGs (Missouri DNR).

For Oklahoma and Colorado, do not take a secondhand summary as settled. Oklahoma’s authorization is codified at 40 CFR 272.1851 and Colorado’s program sits at 6 CCR 1007-3, but as of September 28, 2026 neither state’s characterization-specific provisions could be confirmed against a primary source. OK DEQ’s pages redirect to a general portal, and CDPHE’s waste identification guidance is marked “Currently in revision and not available” (CDPHE generator guidance).

If EPA ever finalizes a non-MSW landfill alternative, Kansas generators will still need a certified lab to run it, and nothing changes before a state rule does.

Does this affect industrial landfills or municipal landfills?

Industrial. EPA’s scoped statement is that it is “considering providing a regulatory alternative to TCLP testing for wastes to evaluate leaching of chemicals from wastes disposed in lined landfills other than municipal solid waste landfills.” That is industrial and monofill disposal, not household trash.

TCLP’s acetic acid exists because the method was designed around co-disposal with decomposing municipal refuse. EPA is asking whether that assumption describes a lined industrial cell that never receives municipal waste. For a facility paying hazardous disposal rates on a stream that fails only under an assumption about a landfill it does not use, that question has a dollar figure attached.

What is EPA asking about solar panels and heterogeneous waste?

The sampling half of the RFI asks whether your organization manages “heterogeneous wastes such as debris, multi-component electronic devices, solar panels,” which waste types create the hardest sampling problems, whether EPA’s existing waste analysis plan guidance is useful, and which non-EPA references you use instead. Solar panels are named in the question itself.

This half of the notice is separate from the leaching half. Any facility that has tried to pull a representative sample from a multi-material assembly has an answer EPA says it wants, and TSDFs have the most to say, since waste analysis plans and profile review run on Method 1311 today.

What to File by November 13, and What to Leave Alone

Leave your compliance program alone. Determinations still happen at the point of generation, testing still means Method 1311, and records still hold for three years. If a vendor or newsletter is selling November 13 as a compliance date, they are selling urgency the primary source does not support.

The work worth doing is short, and it is all data you already own. Pull the streams that carry a D code because of an inorganic constituent near its regulatory level, mark which go to a lined non-MSW landfill, and mark which are highly alkaline, oily or paint-derived. Then decide whether to put that operating experience into docket EPA-HQ-OLEM-2026-7360 or to let other commenters describe your waste streams for you.

If you want a second set of eyes on which streams belong on that list, iSi’s environmental compliance consulting team reviews waste characterization files, tests where generator knowledge will not hold, and documents the determination basis at industrial facilities in 40 states. Send us the D-coded lines you are least sure about and we will tell you which ones a comment to EPA could reach.

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