F006 and F019 are both RCRA-listed hazardous waste codes for wastewater treatment sludges from metal finishing, but they apply to different source processes. F006 sludge comes from electroplating operations. F019 sludge comes from the chemical conversion coating of aluminum. If a single wastewater treatment system receives flows from both kinds of operation, the resulting sludge carries both codes. Because these are listed wastes, the code is set by the process that generated the sludge, not by what a lab test finds in it, so tracing the sludge back to its source operation is the whole ballgame.
What F006 Covers
F006 is defined as wastewater treatment sludge from electroplating operations.1eCFR. 40 CFR 261.31 – Hazardous Wastes From Non-Specific Sources Electroplating uses electrical current to deposit a metal coating onto a substrate. Cadmium, copper, nickel, chromium, and zinc are common plating metals, but the listing applies to electroplating generally rather than to any specific metal. Sludge that settles out of the treatment system captures dissolved heavy metals from spent plating solutions, and that concentrated metal content is what drives the regulatory concern.
The listing reaches beyond the plating bath itself. An EPA interpretive rule clarified that F006 also covers sludges from related metal finishing steps such as anodizing, chemical etching and milling, and cleaning or stripping operations that feed the same wastewater treatment system.2United States Environmental Protection Agency. Regulatory Clarification Regarding F006 Classification for Chemical Etching of Magnesium Several specific processes, however, are carved out of the F006 listing entirely:
- Sulfuric acid anodizing of aluminum
- Tin plating on carbon steel
- Zinc plating (segregated basis) on carbon steel
- Aluminum or zinc-aluminum plating on carbon steel
- Cleaning or stripping tied to tin, zinc, or aluminum plating on carbon steel
- Chemical etching and milling of aluminum
These exclusions cut both ways. A facility whose only qualifying operation is sulfuric acid anodizing of aluminum does not generate F006 sludge from that operation. The sludge may still be hazardous if it exhibits a toxicity characteristic, but it would carry a D-code rather than F006. Over-classifying pushes disposal costs up unnecessarily. Under-classifying, by assuming an operation fits an exclusion when it doesn’t, creates a compliance violation.1eCFR. 40 CFR 261.31 – Hazardous Wastes From Non-Specific Sources
What F019 Covers
F019 is defined as wastewater treatment sludge from the chemical conversion coating of aluminum.1eCFR. 40 CFR 261.31 – Hazardous Wastes From Non-Specific Sources Chemical conversion coating is a different process from electroplating. Rather than using electrical current to deposit a metallic layer, it drives a chemical reaction with the aluminum surface to form a thin protective film, typically for corrosion resistance or as a paint base. Automotive manufacturing is one of the largest sources of F019 sludge, since aluminum parts routinely pass through conversion coating before assembly.3Environmental Protection Agency. Listing Amendment for F019 Wastewater Treatment Sludges, May 2008
F019 is limited to aluminum. Chemical conversion coating performed on steel, magnesium, or any other substrate does not produce F019 sludge. The waste still has to be evaluated against every other listed and characteristic code, but the F019 listing itself requires an aluminum substrate.
F019 Exclusions
Two specific situations are excluded from F019. First, zirconium phosphating in aluminum can washing is excluded when it is the only conversion coating process used. Second, a 2008 amendment created a conditional exclusion for zinc phosphating sludges generated during motor vehicle manufacturing, provided two conditions are met: the waste is not placed on the land before shipment, and it is sent to a landfill meeting the design criteria in 40 CFR 258.40, 264.301, or 265.301.4GovInfo. Hazardous Waste Management System: Identification and Listing of Hazardous Waste; Amendment to Hazardous Waste Code F019 When a motor vehicle manufacturer meets those conditions, the zinc phosphating sludge is not F019 at the point of generation. The exclusion is narrow and depends on careful recordkeeping.
When One Sludge Carries Both Codes
Facilities that run electroplating and chemical conversion coating of aluminum in the same production line often route both waste streams into a single wastewater treatment system. The resulting sludge legitimately carries both F006 and F019. This is common in large metalworking operations where parts pass through multiple finishing steps before the combined wastewater reaches the treatment plant.5Regulations.gov. Delisting Petition for F006/F019 Filter Cake – John Deere Des Moines Works
When both codes apply, both must appear on every manifest, land disposal restriction notification, and waste profile. The treatment standards under 40 CFR Part 268 must be met for each code independently. Meeting the F006 standards does not satisfy the F019 obligation, or vice versa.
How to Make the Determination
The classification of a sludge as F006 or F019 runs on process knowledge, not laboratory results. Both are listed wastes, so their hazardous status is fixed by the source process. Sludge from a qualifying electroplating wastewater treatment system is F006 no matter what a TCLP analysis shows. Sludge from a qualifying chemical conversion coating of aluminum operation is F019 on the same principle.
Process knowledge means documenting exactly which industrial operations generated the wastewater that produced the sludge. That means tracing the waste stream from the plating bath or coating tank, through any intermediate treatment steps, to the final sludge collection point. Production logs, piping and flow diagrams, and chemical purchase records all support the determination. Under 40 CFR 262.11, a generator relying on process knowledge must keep records showing the process that produced the waste along with its composition and properties.6eCFR. 40 CFR 262.11 – Hazardous Waste Determination and Recordkeeping
Process knowledge does not end the analysis. Every generator must evaluate the waste against all four hazardous waste lists (F, K, P, and U) and determine, by testing or knowledge, whether it also exhibits any of the four characteristics: ignitability, corrosivity, reactivity, and toxicity. The Toxicity Characteristic Leaching Procedure is the standard analytical method for the toxicity characteristic. If the sludge exceeds the regulatory threshold for a metal on the TCLP, it picks up the corresponding D-code on top of the F-code. The D-code does not replace the F-listing.
A practical checklist for the determination:
- Identify every process that discharges to the wastewater treatment system generating the sludge.
- For each process, decide whether it is electroplating covered by F006, whether it is a related metal finishing step swept in by the EPA interpretive rule, or whether it falls within one of the six F006 exclusions.
- Ask separately whether any process is chemical conversion coating of aluminum, and if so, whether it falls under the zirconium phosphating or 2008 zinc phosphating exclusion.
- If the answer to the F006 question is yes, apply F006. If the answer to the F019 question is yes, apply F019. If both, apply both.
- Run the characteristic evaluation regardless, and add any D-codes that apply.
- Keep the process flow diagrams, production records, and any test data that support the call.
Why the Code Sticks: Mixture and Derived-From Rules
Two rules make F006 and F019 classification harder to shed than generators sometimes assume. Under the mixture rule, any solid waste mixed with a listed hazardous waste is itself a listed hazardous waste.7eCFR. 40 CFR 261.3 – Definition of Hazardous Waste Combining F006 sludge with a non-hazardous stream in a drum or treatment tank makes the whole mixture F006. Consolidating waste streams without thinking through this rule is a common trap.
The derived-from rule works in the same direction. Any residue from treating, storing, or disposing of a listed hazardous waste remains listed, including sludge, ash, leachate, and spill residue.7eCFR. 40 CFR 261.3 – Definition of Hazardous Waste Dewatered F019 sludge is still F019. Incinerated F019 sludge produces F019 ash. These rules persist until the waste is formally delisted or falls within a regulatory exclusion.
What Getting the Code Wrong Costs
Assigning the wrong code cascades into every downstream requirement: treatment standards, manifest entries, LDR certifications, and the permitted status of the receiving facility. Civil penalties for RCRA violations can reach $124,426 per day, adjusted annually for inflation.8eCFR. 40 CFR Part 19 – Adjustment of Civil Monetary Penalties for Inflation Under 42 U.S.C. 6928(d), knowing violations, such as sending hazardous waste to an unpermitted facility, making false statements on manifests, or treating waste without a permit, can bring imprisonment and substantial fines. “Knowing” means aware of the conduct, not aware that the conduct was illegal.9GovInfo. 42 USC 6928 – Federal Enforcement
The enforcement pattern most often seen with F006 and F019 involves facilities that commingle waste streams and use only one code when both apply, or facilities that rely on an exclusion without maintaining documentation to back it up. Inspectors compare process flow diagrams to manifest records and check whether the codes reflect the actual operations. Gaps in the documentation trail work against the generator.