The EPA’s Replacement for the H141 Code on Hazardous Waste Reporting
On January 1, 2027, EPA removes management method code H141 from the e-Manifest and the Biennial Report. The catch-all storage and transfer code gives way to 24 S-codes, each one pairing storage and transfer with the final management method the waste will receive at end of life. That added detail keeps the cradle-to-grave record intact for waste that moves through a transfer facility.
EPA’s published list of management method codes groups them under four headings: Reclamation and Recovery; Destruction or Treatment Prior to Disposal at Another Site; Disposal; and Transfer Off Site. On state code lists updated for the change, such as Montana DEQ’s December 2025 list, all 24 S-codes appear under Transfer Off-Site, alongside H141. To make them easier to scan, this glossary sorts the S-codes by the final method each one points to, using the other three headings. Each S-code number matches the H-code for the same final method, so S040 points to incineration, which EPA lists as H040.
Each entry below includes two descriptions. The short description follows EPA’s official code wording, with abbreviations spelled out, and is intentionally brief. The in-depth description explains, in plain terms, what the underlying recovery, treatment, or disposal method involves. EPA has not published a deeper technical definition for each S-code, so the in-depth entries draw on federal hazardous waste regulations and EPA guidance for each method. Where a regulation is referenced, it describes the general method, not the S-code itself. A source line follows each entry, and full references are listed at the end.
Short description: Waste stored and transferred for metals recovery.
In-depth: Metals recovery covers processes such as smelting, acid leaching, or electrolytic recovery used to extract metal value from spent materials, sludges, or scrap containing recoverable metals. Under EPA’s hazardous waste recycling regulations, a material is considered reclaimed when it is processed to recover a usable product, and metals recovery operations fall under that definition. Recovered metals can be returned to industrial use, reducing the volume of waste that would otherwise require disposal.
Short description: Waste stored and transferred for mercury recovery.
In-depth: Mercury recovery relies primarily on thermal retorting, a process that heats mercury-contaminated waste in a sealed, vacuum-controlled chamber to vaporize the mercury, then condenses the vapor back into liquid form for reuse. Wastes containing more than 260 milligrams of mercury per kilogram generally must be retorted or incinerated before disposal under federal treatment standards. Retorting reduces the total mercury content of the residual waste and lowers how readily any remaining mercury can leach out.
Short description: Waste stored and transferred for deployment/deactivation of airbag waste.
In-depth: Undeployed airbag modules and inflators contain propellant chemicals that give them the hazardous characteristics of ignitability and reactivity. Deployment, whether triggered electronically or through a controlled process, consumes that propellant and removes those hazardous characteristics from the module. EPA guidance treats used airbag modules that can safely be deployed electronically, and are then legitimately recycled for metal value, as exempt scrap metal. That exemption does not extend to modules with recalled, defective inflators, which pose safety risks during deployment.
Short description: Waste stored and transferred for solvents recovery.
In-depth: Solvent recovery most commonly uses distillation, in which spent solvent is heated to its boiling point so the solvent vaporizes, separates from contaminants, and condenses back into a purified liquid that can be reused. Distillation can recover a large majority of the original solvent volume, leaving a smaller quantity of concentrated still bottoms that require further management as hazardous waste. Reclaimed solvent that meets the specifications of the original product can, in some cases, no longer be classified as a solid waste at all.
Short description: Waste stored and transferred for other recovery or reclamation for reuse.
In-depth: This code serves as a catch-all for recovery methods that do not fit neatly into the other named recovery categories, including specialized reclamation processes built around a specific waste stream or material type. EPA’s hazardous waste recycling regulations define reclamation broadly, covering any process that regenerates a spent material or recovers a usable product from it. Facilities using proprietary or waste-specific recovery methods would typically report under this code.
Short description: Stored and transferred for fuel blending prior to energy recovery.
In-depth: Fuel blending combines compatible hazardous wastes with fuel value into a blended fuel suited to a downstream burner. The blending happens at one facility, and the finished fuel is then burned for energy recovery at another site. EPA’s parallel H061 code describes fuel blending prior to energy recovery at another site, covering waste generated on site or received from off site. This code places the stored and transferred waste one step earlier in the chain than S050: it is headed to a fuel blender first, and only after blending does it reach a boiler or industrial furnace. The blended fuel generally remains a hazardous waste, so the unit that eventually burns it is still subject to federal standards for boilers and industrial furnaces.
Short description: Stored and transferred for fuel blending prior to energy recovery.
In-depth: Fuel blending combines compatible hazardous wastes with fuel value into a blended fuel suited to a downstream burner. The blending happens at one facility, and the finished fuel is then burned for energy recovery at another site. EPA’s parallel H061 code describes fuel blending prior to energy recovery at another site, covering waste generated on site or received from off site. This code places the stored and transferred waste one step earlier in the chain than S050: it is headed to a fuel blender first, and only after blending does it reach a boiler or industrial furnace. The blended fuel generally remains a hazardous waste, so the unit that eventually burns it is still subject to federal standards for boilers and industrial furnaces.
Short description: Waste stored and transferred for metals recovery.
In-depth: Metals recovery covers processes such as smelting, acid leaching, or electrolytic recovery used to extract metal value from spent materials, sludges, or scrap containing recoverable metals. Under EPA’s hazardous waste recycling regulations, a material is considered reclaimed when it is processed to recover a usable product, and metals recovery operations fall under that definition. Recovered metals can be returned to industrial use, reducing the volume of waste that would otherwise require disposal.
Short description: Waste stored and transferred for mercury recovery.
In-depth: Mercury recovery relies primarily on thermal retorting, a process that heats mercury-contaminated waste in a sealed, vacuum-controlled chamber to vaporize the mercury, then condenses the vapor back into liquid form for reuse. Wastes containing more than 260 milligrams of mercury per kilogram generally must be retorted or incinerated before disposal under federal treatment standards. Retorting reduces the total mercury content of the residual waste and lowers how readily any remaining mercury can leach out.
Short description: Waste stored and transferred for deployment/deactivation of airbag waste.
In-depth: Undeployed airbag modules and inflators contain propellant chemicals that give them the hazardous characteristics of ignitability and reactivity. Deployment, whether triggered electronically or through a controlled process, consumes that propellant and removes those hazardous characteristics from the module. Once deployed, the airbag waste no longer poses the same handling risk and can generally be managed under standard scrap metal recycling rules. This process became a significant compliance focus following large-scale vehicle recalls involving defective inflators.
Short description: Waste stored and transferred for solvents recovery.
In-depth: Solvent recovery most commonly uses distillation, in which spent solvent is heated to its boiling point so the solvent vaporizes, separates from contaminants, and condenses back into a purified liquid that can be reused. Distillation can recover a large majority of the original solvent volume, leaving a smaller quantity of concentrated still bottoms that require further management as hazardous waste. Reclaimed solvent that meets the specifications of the original product can, in some cases, no longer be classified as a solid waste at all.
Short description: Waste stored and transferred for other recovery or reclamation for reuse.
In-depth: This code serves as a catch-all for recovery methods that do not fit neatly into the other named recovery categories, including specialized reclamation processes built around a specific waste stream or material type. EPA’s hazardous waste recycling regulations define reclamation broadly, covering any process that regenerates a spent material or recovers a usable product from it. Facilities using proprietary or waste-specific recovery methods would typically report under this code.
Short description: Stored and transferred for fuel blending prior to energy recovery.
In-depth: Fuel blending combines compatible hazardous wastes with fuel value into a blended fuel suited to a downstream burner. The blending happens at one facility, and the finished fuel is then burned for energy recovery at another site. EPA’s parallel H061 code describes fuel blending prior to energy recovery at another site, covering waste generated on site or received from off site. This code places the stored and transferred waste one step earlier in the chain than S050: it is headed to a fuel blender first, and only after blending does it reach a boiler or industrial furnace. The blended fuel generally remains a hazardous waste, so the unit that eventually burns it is still subject to federal standards for boilers and industrial furnaces.
Short description: Stored and transferred for energy recovery.
In-depth: Energy recovery means burning hazardous waste as a fuel so its heat value is put to use. Federal rules regulate this burning in two kinds of units, boilers and industrial furnaces, together known as BIFs, under 40 CFR Part 266, Subpart H. A boiler recovers and exports energy as steam, heated fluid, or heated gases. An industrial furnace, such as a cement kiln or lime kiln, is an integral part of a manufacturing process and uses the heat to recover materials or energy. This code tells the reader that the stored and transferred waste is headed to one of these units to serve as fuel. EPA’s parallel H050 code covers energy recovery at the receiving site, including any on-site fuel blending done before burning.
Short description: Waste stored and transferred for incineration.
In-depth: Incineration destroys the organic constituents in hazardous waste through high-temperature combustion and substantially reduces the waste’s volume. EPA describes the parallel H040 code as thermal destruction other than use as a fuel, which is what separates incineration from energy recovery under S050. Metals do not combust, so incineration is less effective for metal-bearing wastes. Hazardous waste incinerators are regulated under 40 CFR Parts 264 and 265, Subpart O, and any ash or residue left behind must still be managed according to its own hazard classification.
Short description: Waste stored and transferred for open burning/open detonation.
In-depth: Open burning and open detonation, often called OB/OD, is a treatment method reserved almost exclusively for waste explosives and reactive military munitions that cannot be safely managed through any other treatment technology. EPA prohibited open burning of hazardous waste generally in 1980, preserving only this narrow exception for materials with the potential to detonate. OB/OD releases combustion byproducts directly into the open air instead of through a controlled emission system. In March 2024, EPA proposed revisions that would tighten when and how OB/OD can be used, and as of mid-2026 that rule remains a proposal.
Short description: Waste stored and transferred for thermal desorption.
In-depth: Thermal desorption is a physical separation process. It heats contaminated solids, sludges, or filter cakes to a temperature high enough to volatilize organic contaminants, which are then carried off by a gas stream and captured for further treatment elsewhere. The process separates contaminants from the material without destroying them, so it is often paired with a downstream treatment step for the resulting vapor stream. This method is widely used to recover oil from oil-bearing hazardous secondary materials without incinerating the underlying solids.
Short description: Waste stored and transferred for chemical treatment.
In-depth: Chemical treatment covers a broad set of reactions, such as oxidation, reduction, precipitation, or chemical fixation, used to alter the composition of a waste and reduce its toxicity, mobility, or volume. The specific chemistry applied depends on the waste stream and the contaminants of concern. This category is distinct from neutralization and stabilization, which EPA tracks as their own separate codes because they are common enough treatment methods to warrant individual reporting.
Short description: Waste stored and transferred for biological treatment.
In-depth: Biological treatment uses microorganisms to break down organic constituents in a waste stream, converting them into simpler, less hazardous compounds. EPA’s own waste management reporting framework separately defines biological treatment as a category distinct from chemical and physical methods. This approach is most often applied to wastewaters and biodegradable organic wastes.
Short description: Waste stored and transferred for polymerization.
In-depth: Polymerization treatment forms complex, high-molecular-weight solids by chemically linking smaller monomer molecules together, typically in high-organic-content, non-wastewater streams that serve as components in plastics manufacturing. Once polymerized, the resulting solid is far less mobile and less likely to leach than the original waste. This is one of the specific federal Land Disposal Restriction treatment standards long recognized under EPA’s technology-based treatment codes.
Short description: Waste stored and transferred for physical treatment only.
In-depth: Physical treatment changes the physical form of a waste, through methods such as filtration, settling, or separation, without altering its underlying chemical composition. It is typically used to concentrate, dewater, or separate waste components ahead of a later treatment or disposal step. Because no chemical reaction takes place, physical treatment alone reduces a waste’s volume or handling characteristics without necessarily reducing its inherent toxicity.
Short description: Waste stored and transferred for stabilization.
In-depth: Stabilization is a physical or chemical process that reduces the mobility of hazardous constituents in a waste or eliminates free liquids, typically by mixing the waste with a binder such as Portland cement or lime and pozzolans, then curing the mixture into a solid mass. This process is also known as fixation or solidification. Stabilization reduces the likelihood that hazardous constituents will leach into the environment once the waste is disposed of, even when those constituents remain present in the cured mass.
Short description: Waste stored and transferred for stabilization to remove hazardous waste characteristics or to achieve delisting levels.
In-depth: This code applies when stabilization is performed for one of two specific outcomes: removing a waste’s hazardous characteristic entirely, such as its corrosivity or toxicity, or reducing constituent concentrations enough to support a facility-specific delisting petition. Delisting is a formal federal process in which a generator petitions EPA or an authorized state to exclude a specific waste stream from the hazardous waste lists, based on data showing it no longer meets the criteria for which it was originally listed. Because delisting decisions are waste- and facility-specific, a stabilized waste at one location may qualify while a similar waste elsewhere would not.
Short description: Waste stored and transferred for combination of chemical, biological, and/or physical treatment.
In-depth: Many waste streams require more than one treatment mechanism to reach an acceptable endpoint, and this code captures those multi-step processes, such as a chemical precipitation step followed by physical dewatering, or a biological step paired with chemical adjustment. Facilities running integrated treatment systems would generally report under this combined code instead of one of the individual treatment categories.
Short description: Waste stored and transferred for neutralization only.
In-depth: Neutralization treats a waste’s corrosivity characteristic by adding acids, bases, or water to bring its pH into an acceptable range. Federal treatment standards define an acceptable neutralized range as greater than 2 and less than 12.5, measured in the aqueous residual. Elementary neutralization units that treat waste solely for this characteristic are subject to a narrower set of regulatory requirements than full treatment facilities, reflecting how straightforward and low-risk the process generally is compared to other treatment methods.
Short description: Waste stored and transferred for evaporation.
In-depth: Evaporation reduces the liquid volume of a waste stream by driving off water or other volatile components, concentrating the remaining solids or contaminants into a smaller residual volume. EPA’s own recovery and disposal operation codes list evaporation alongside drying, calcination, and precipitation as physical and chemical treatment methods. It is frequently used as a volume-reduction step ahead of further treatment or disposal, particularly for wastewaters.
Short description: Waste stored and transferred for other treatment.
In-depth: Like its recovery counterpart at S039, this code functions as a catch-all for treatment methods that do not fall under one of the specifically named categories elsewhere in the S-code list. It covers waste-specific or proprietary treatment technologies that reduce toxicity, mobility, or volume through mechanisms not captured by the chemical, biological, physical, stabilization, or neutralization codes individually.
Short description: Waste stored and transferred for surface impoundment that will be closed as landfill.
In-depth: A surface impoundment is a natural depression or engineered excavation, typically formed of earthen materials, designed to hold liquid waste or waste containing free liquids, such as a lagoon or holding pond. When an impoundment reaches the end of its operating life and the owner chooses to leave waste in place instead of removing it, the unit must be closed following landfill closure requirements, including a cap and long-term post-closure monitoring. This code tracks that specific end-of-life pathway, distinct from an impoundment that continues operating or is closed by waste removal.
Short description: Waste stored and transferred for land treatment or application.
In-depth: Land treatment applies or incorporates hazardous waste directly into the soil surface, relying on natural biological and chemical processes in the soil to degrade the waste’s hazardous constituents over time. Federal regulations classify land treatment facilities as disposal facilities whenever the waste is intended to remain in the soil after the facility closes, distinguishing this method from temporary storage or treatment units. This approach is used far less today than in past decades, given the more stringent monitoring and closure requirements now applied to land-based units.
Short description: Stored and transferred for landfill (with prior treatment and/or stabilization).
In-depth: Federal land disposal restrictions generally prohibit placing untreated hazardous waste directly into a landfill. This code reflects that requirement by tracking waste that receives a treatment step, commonly stabilization, chemical treatment, or incineration, before it goes to final landfill disposal. The treatment standard a given waste must meet depends on its specific hazardous characteristics or listing, and it is designed to reduce the chance that hazardous constituents will leach out of the landfill over time.
Short description: Stored and transferred for deep well or underground injection.
In-depth: Underground injection places liquid hazardous waste into a well drilled deep enough to reach a geologic formation below any underground source of drinking water, isolating the waste from groundwater supplies. Wells used for this purpose are classified federally as Class I hazardous waste injection wells and are subject to strict siting, construction, and monitoring requirements, including a minimum siting depth below the lowermost formation containing drinking water within a quarter mile of the well. Many hazardous wastes are prohibited from underground injection unless they are first treated to meet applicable federal standards.
Full references for the citations above, in order of appearance:
The Amlon Group’s material recovery and recycling technologies are changing the way companies handle their industrial wastes and byproducts.
Get answers to our most frequently asked questions below or contact us directly.
The Amlon Group’s material recovery and recycling technologies are changing the way companies handle their industrial wastes and byproducts.
Get answers to our most frequently asked questions below or contact us directly.