The U.S. Environmental Protection Agency is asking chemical manufacturers, waste generators and laboratories whether its long-established hazardous-waste testing methods need to change.

The review includes the Toxicity Characteristic Leaching Procedure (TCLP), a laboratory method used to assess how certain contaminants may leach from waste under specified conditions.

The comment deadline is November 13, 2026, according to the Federal Register notice. But EPA has not yet adopted a replacement for TCLP or changed the existing hazardous-waste toxicity thresholds.

That distinction matters for industrial facilities managing chemical production residues, wastewater-treatment sludge, spent coating materials and other potentially regulated wastes.

The current review provides an opportunity to raise documented testing problems. It does not authorize businesses to replace required methods with alternative procedures immediately.

For procurement, quality-control and environmental, health and safety (EHS) teams, the useful response is to examine existing analytical records, identify where testing creates uncertainty and understand what a future change might mean for waste classification.

EPA’s 2026 Review Covers More Than One Laboratory Test

On September 14, 2026, EPA published a Federal Register request for information on SW-846 testing and waste sampling.

SW-846 is EPA’s collection of analytical methods and guidance used to support decisions under the Resource Conservation and Recovery Act (RCRA).

Some methods are used to determine whether a waste is hazardous. Others support treatment evaluations, regulatory compliance and environmental investigations.

The agency is requesting information in four main areas:

• Challenges with representative waste sampling.
• Technical and operational problems involving TCLP Method 1311.
• Potential uses of alternative leaching methods, including the Leaching Environmental Assessment Framework (LEAF).
• Other SW-846 method improvements and data needs.

The request includes input from chemical manufacturers, waste-treatment facilities, laboratories, researchers, government agencies and other interested stakeholders.

EPA says the information will help determine what action, if any, should follow.

That means the notice is an information-gathering exercise rather than a finalized regulation.

Why the November Deadline Needs Careful Attention

The published Federal Register notice gives November 13, 2026, as the date by which comments should be received for consideration in short-term method updates.

EPA’s separate summary webpage currently describes a comment period continuing through November 14.

Because these dates differ, businesses intending to respond should work to the earlier November 13 deadline stated in the formal notice and confirm the current instructions in the official docket.

The relevant docket identification is EPA-HQ-OLEM-2026-7360.

The notice also explains that EPA may consider later submissions where practicable, but that possibility should not be treated as an extension.

What TCLP Actually Measures

TCLP was developed to evaluate how selected substances could move from a waste into liquid under specified landfill-related conditions.

EPA’s Method 1311 documentation describes its application to liquid, solid and multiphase wastes.

The method uses controlled extraction conditions and subsequent analysis of the resulting liquid.

The purpose is not to measure every environmental risk associated with a waste.

Instead, it produces an analytical result that can be evaluated against specific regulatory requirements.

For example, the method is used in determining whether certain wastes exhibit the RCRA toxicity characteristic.

It is also referenced in applicable land disposal restriction requirements.

These regulatory uses make TCLP different from many optional screening methods.

EPA identifies TCLP as a method-defined parameter. Where regulations require that measurement, the prescribed method cannot simply be modified or replaced at the laboratory’s discretion.

TCLP Is Not the Same as Total-Metal Analysis

A total-metal test measures the amount of a specified element in the original sample under the relevant analytical procedure.

TCLP evaluates the concentration of designated contaminants in the resulting extract.

These results have different reporting bases.

A laboratory might report total lead as milligrams per kilogram of waste.

The TCLP result for lead is expressed as milligrams per litre of extract.

Both measurements can provide useful information, but their numerical values are not directly interchangeable.

That distinction is especially important when a waste contains metals that may be present in relatively insoluble forms.

A high total concentration does not necessarily mean the same proportion will become available during the extraction.

Conversely, a material cannot automatically be considered safe for every disposal environment simply because one standardized leaching test produces a comparatively low result.

Why EPA Is Questioning Some TCLP Assumptions

TCLP was designed around specified conditions associated with municipal solid waste landfills.

However, industrial wastes can behave differently depending on their composition and disposal environment.

EPA’s September notice identifies several concerns raised previously about the method.

Some involve highly alkaline wastes, where the prescribed conditions may not adequately represent relevant contaminant mobility.

Others concern oily wastes, certain paint wastes, chelating substances and processes in which oxidation-reduction reactions influence chemical behavior.

EPA also notes concerns about applying TCLP to environments that differ substantially from the municipal landfill conditions the method was designed to represent.

These concerns should not be interpreted as proof that TCLP produces incorrect results for every such material.

They identify situations where more evidence may be needed to understand the relationship between standardized laboratory extraction and actual environmental conditions.

Why This Matters for Chemical Manufacturing Residues

Consider an industrial facility using iron salts for wastewater phosphorus removal.

Chemical precipitation can produce sludge containing iron compounds, phosphorus and other substances present in the treated water.

The site’s explanation of ferrous and ferric salts in phosphorus removal describes why chemical selection, treatment conditions and solids separation affect the resulting process.

The composition of that sludge depends on the actual wastewater and treatment system.

A certificate confirming the purity of the purchased iron salt cannot establish the regulatory classification of the waste generated after treatment.

The facility must evaluate the waste stream itself under the applicable rules.

The same principle applies to other manufacturing residues.

A material’s original product specification does not automatically describe its final condition after processing, contamination or chemical transformation.

Total-Metal Results Can Sometimes Help Avoid Unnecessary Testing

A particularly useful part of hazardous-waste evaluation is understanding when total-composition data can help establish whether TCLP testing is necessary.

Under appropriate conditions, a total analysis may show that a substance is present at such a low concentration that the corresponding TCLP threshold could not be exceeded even if the entire measured quantity entered the extract.

Consider a hypothetical completely solid waste sample containing 80 milligrams of total lead per kilogram.

For the relevant screening calculation, the TCLP liquid-to-solid extraction ratio is 20 litres per kilogram.

Assuming every milligram of lead entered the extraction liquid:

Maximum theoretical lead concentration = 80 mg/kg ÷ 20 L/kg = 4 mg/L

The RCRA toxicity characteristic regulation in 40 CFR 261.24 specifies a threshold of 5.0 mg/L for lead in the TCLP extract.

In this simplified example, the maximum theoretical concentration is below that threshold.

EPA’s SW-846 guidance recognizes that sufficiently reliable total-composition data can sometimes support a determination that TCLP testing is unnecessary for a particular constituent.

However, this calculation has strict limitations.

It assumes a representative sample of the appropriate solid-waste type and a valid total analysis.

It does not evaluate other contaminants, listed hazardous-waste classifications or other hazardous characteristics.

For wastes containing both liquid and solid phases, the appropriate calculations differ.

What Happens When the Screening Calculation Exceeds the Limit?

Suppose the hypothetical waste instead contains 160 mg/kg of total lead.

The calculation becomes:

160 mg/kg ÷ 20 L/kg = 8 mg/L

That exceeds the 5 mg/L regulatory level.

However, it does not prove that the material exhibits the toxicity characteristic.

The calculation assumes complete release of the lead.

The actual TCLP result could be lower because not all lead necessarily enters the extract.

Additional appropriate evidence or testing may therefore be needed to determine the waste’s status.

This illustrates why the calculation works as a possible screening tool rather than a universal substitute for the prescribed analytical procedure.

Could LEAF Eventually Provide a More Flexible Alternative?

EPA’s review also addresses the Leaching Environmental Assessment Framework.

LEAF was developed to examine how environmental conditions and material characteristics influence the release of inorganic constituents.

The EPA LEAF methods and technical guidance describe four related methods:

• Method 1313 evaluates liquid-solid partitioning across different extract pH conditions.
• Method 1314 examines leaching as a function of liquid-to-solid ratio using an up-flow column.
• Method 1315 evaluates mass-transfer rates from monolithic or compacted granular materials.
• Method 1316 evaluates partitioning across different liquid-to-solid ratios using parallel batch extraction.

These methods address questions that cannot always be resolved through one standardized extraction condition.

For example, a solidified waste may behave differently when exposed to changing pH or when water contacts its surface over time.

LEAF methods can provide additional evidence for assessing potential environmental releases under defined scenarios.

However, the published LEAF methods were validated for inorganic constituents. EPA’s September 2026 notice states that work on adapting the framework for organic substances remains in development.

LEAF Is Not Yet a General Replacement for Required TCLP Tests

EPA is considering whether LEAF-based approaches could provide a regulatory alternative for certain wastes disposed of in lined landfills other than municipal solid waste landfills.

That possibility is still under consideration.

It is not an adopted blanket substitution rule.

Where existing RCRA provisions require TCLP, the applicable regulatory method remains controlling unless and until the rules are changed.

Facilities should not use a favorable LEAF result alone to declare that a waste meets an existing TCLP-based regulatory requirement.

The correct method depends on the legal question being answered.

Why Sample Representativeness May Matter More Than Test Sensitivity

A technically correct laboratory procedure cannot compensate for a sample that does not represent the relevant waste stream.

Manufacturing residues may contain layers, variable moisture, different particle sizes or inconsistent contaminant concentrations.

A sample collected from one convenient location may not reflect the composition of an entire waste batch.

EPA’s review specifically seeks information about sampling challenges involving heterogeneous wastes.

This issue is relevant to chemical processing facilities that generate filter cakes, mixed sludge, spent absorbents and other nonuniform materials.

For EHS and quality teams, the central questions are whether the sampling plan addresses expected variability and whether the laboratory received material appropriate to the analytical objective.

Where regulatory decisions depend on the result, the sampling design and test selection should be established by qualified personnel.

Repeated testing of an unrepresentative sample does not solve the underlying problem.

Keep Product Compliance and Waste Classification Separate

Chemical manufacturers frequently maintain several sets of analytical documents for the same general material or production process.

They should not be treated as interchangeable.

For example, testing water-soluble chromium(VI) in finished cement under a European product restriction answers a different question from determining the toxicity characteristic of a waste under the U.S. RCRA framework.

The site’s article on ferrous sulfate and chromium(VI) compliance in cement illustrates how a specific product requirement depends on its prescribed measurement.

That test does not automatically establish a waste’s TCLP classification.

A certificate of analysis (CoA) reports selected analytical findings associated with an identified product lot.

A product specification defines the agreed acceptance requirements for the supplied material.

A safety data sheet (SDS) communicates chemical hazards and safe-use information.

An independent waste laboratory report provides evidence for the particular waste sample, analytical method and constituents tested.

A facility must connect the correct evidence to the correct regulatory decision.

What Industrial Facilities Should Review Before November 13

Companies considering a response to EPA’s request for information can begin with their actual laboratory and waste-management records.

The most useful information is likely to concern specific problems encountered with sampling, testing or interpretation.

For example, a facility may have documented situations where the physical condition of a waste made representative sampling difficult.

A laboratory may have evidence of practical challenges applying prescribed separation or extraction steps to particular waste types.

A treatment facility may have comparative data showing how results differ when the same material is assessed under different relevant environmental conditions.

Where information is suitable for public disclosure, it can help EPA evaluate whether revised guidance, improved methods or additional regulatory flexibility would provide measurable benefits.

The Federal Register notice requests supporting information about technical challenges, potential benefits, costs and relevant data.

Businesses should not submit confidential formulation details, proprietary information or other restricted material through the public docket.

Before submitting comments, responsible personnel should review the notice and the current docket instructions.

For facilities that do not intend to comment, this is still an appropriate time to check their existing waste-characterization records.

The review should establish whether waste descriptions, analytical methods, sampling procedures and supporting documentation remain suitable for the decisions being made.

The Current Rules Still Apply While EPA Reviews Alternatives

EPA’s 2026 request for information is an important development because it recognizes practical limitations in longstanding hazardous-waste testing approaches.

It also creates space for companies and laboratories to provide evidence about how waste characteristics and disposal conditions affect analytical interpretation.

But no general change to TCLP compliance requirements should be assumed from the request itself.

For chemical manufacturers, the immediate priority is maintaining valid waste determinations while identifying where the existing evidence is incomplete.

The strongest position combines representative sampling, appropriate laboratory methods, a clear understanding of reporting units and careful interpretation of the regulatory thresholds.

If EPA eventually adopts changes, businesses with organized analytical records and controlled testing procedures will be better positioned to evaluate their effects.

Until then, a proposed alternative method is not an approved replacement, and a favorable laboratory number is only as useful as the regulatory question it actually answers.