Foundry Sand Reuse in North Carolina

Planning to reuse spent foundry sand in North Carolina? This guide covers the rules that apply, the tests that decide how the sand can be managed, and what DEQ needs before the sand can be reused.

Key terms

Spent foundry sand

Foundries bond silica sand into molds and cores for casting metal. The sand is reused many times in the plant. Spent foundry sand is molding and core sand that can no longer make molds or cores.

Green sand and chemically bonded sand

Green sand is bonded with clay, usually bentonite, plus water and additives such as carbon. Chemically bonded sand uses resin binders. Most cores are chemically bonded. The binder system affects what the spent sand contains.

Beneficial reuse

Beneficial reuse puts a waste material to productive use instead of disposing of it. In North Carolina, material that meets the statute’s recovered material conditions is not regulated as solid waste. Starting January 1, 2027, DEQ can also issue a beneficial use determination for nonhazardous solid waste at a particular site or in a particular application.

TCLP

The Toxicity Characteristic Leaching Procedure (EPA Method 1311) measures how much of certain contaminants can leach from a sample. It is one part of deciding whether a waste is hazardous.

What’s in your spent sand?

Spent sand carries what the casting process added: binder residue, metal fines, and burnt core material. The alloy matters most. Sand from iron, steel, and aluminum foundries is the most commonly reused. Sand from leaded brass and bronze foundries is often regulated as hazardous waste.

Keep each stream separate. Baghouse dust, shotblast fines, cupola slag, broken cores, and core room sweepings need their own evaluation. Mixing them into spent sand can change how the whole load is managed. Track the alloys cast, the binder system, and any process changes.

North Carolina’s reuse rules

Recovered material

North Carolina’s reuse statute is G.S. 130A-309.05. Under subsection (c), recovered material does not need a solid waste permit. DEQ may require the owner to show that the material meets every condition:

1. it is managed as a valuable commodity, in a way that fits its end use;
2. at least 75 percent, by weight or volume, of the material stored at a facility on January 1 leaves through sale, use, or reuse by December 31;
3. the material and its products are not discharged, spilled, leaked, or placed where they can enter land, air, or water;
4. it is not a hazardous waste and was not recovered from a hazardous waste; and
5. it has no significant foreign constituents that make it unfit for sale or its intended use.

Material accumulated speculatively, as defined in 40 CFR Part 261, does not qualify. It stays regulated as solid waste.

Beneficial use determinations from January 1, 2027

S.L. 2026-41, Section 12.18 adds subsection (d) to G.S. 130A-309.05, effective January 1, 2027. It lets DEQ decide whether nonhazardous solid waste may be used at a particular site or in a particular application instead of being disposed of. DEQ may:

1. authorize management of a specified type of nonhazardous solid waste at a site that is not a permitted solid waste facility; or
2. issue a beneficial use determination with conditions for use in construction, land application, or other projects.

From that date, DEQ may also require a person to get a beneficial use determination instead of relying on the recovered material conditions.

Fill

Under 15A NCAC 13B .0562, permit-free beneficial fill may use only inert debris waste. Fill made with other solid waste needs a solid waste permit.

Working with DEQ

• Recovered material: no application is needed. Be ready to show DEQ that the sand meets each subsection (c) condition.
• Who files: starting January 1, 2027, a person seeking a beneficial use determination applies to DEQ.
• How: submit the information on forms DEQ prescribes, plus anything else DEQ needs to decide.
• Review: DEQ also considers research and information from others on possible hazards of the waste type.
• Conditions: DEQ may require a demonstration that the waste is managed safely. It may require periodic testing and conditions that keep the material out of land, air, and water.
• Term and renewal: approvals last no longer than five years. Request renewal at least 60 days before the approval expires.
• Annual report: the applicant reports material use each year and certifies compliance with the solid waste laws and rules.
• After approval: DEQ may suspend, revoke, or modify an authorization for noncompliance or new information. DEQ posts approved determinations on its website.

DEQ Solid Waste Section: (919) 707-8200.

Hazardous waste determination

North Carolina adopts the federal hazardous waste rules by reference in 15A NCAC 13A, including later amendments and editions. Rule .0106 adopts 40 CFR Part 261, and rule .0107 adopts Part 262.

North Carolina adds a few generator requirements. Small and large quantity generators must keep at least two feet of aisle space in a central accumulation area. Generators must keep inspection records for three years. Hazardous foundry sand cannot qualify as recovered material.

Under 40 CFR 262.11, the foundry must decide whether its spent sand is hazardous:

1. Make the determination at the point of generation, before mixing or dilution. Repeat it if the waste may have changed.
2. Check whether the waste is excluded from the hazardous waste rules.
3. Check whether it matches a listed hazardous waste.
4. Check for hazardous characteristics, including toxicity. Use knowledge of the materials and process, testing, or both. Test when knowledge alone is not enough.

Small and large quantity generators must keep records supporting the determination for at least three years after the waste was last sent for treatment, storage, or disposal.

TCLP testing and limits

Tell the lab the alloys cast, the binder system, and which streams the sample includes. Use representative samples. Agree on the sampling plan with the lab, DEQ, and the receiving site before collecting.

A waste is hazardous for toxicity if its TCLP extract meets or exceeds any limit in 40 CFR 261.24. The limits for the RCRA metals are:

Passing TCLP addresses toxicity for the substances tested. It does not approve reuse or rule out other reasons a waste may be hazardous. See material testing for sampling basics.

A beneficial use determination may require periodic testing of the waste. For landfill cover, DEQ’s alternative cover guidance requires a TCLP analysis at the source before use, submitted with the landfill’s operation plan revision.

Finding a reuse destination

EPA’s 2014 risk assessment found three uses protective of health and the environment for silica-based spent sand from iron, steel, and aluminum foundries: manufactured soil, soil-less potting media, and road subbase. EPA and USDA support those uses. The finding does not cover sand from brass or bronze foundries, olivine sand, or sand mixed with other foundry wastes such as baghouse dust or cupola slag. EPA defers to state programs, so the state rules on this page still decide each use.

DEQ’s guidance on approved alternative daily cover materials lists foundry sand. Once DEQ approves an alternative cover at one sanitary landfill, it may be used at all sanitary landfills in the state (G.S. 130A-295.6(h1)). The foundry sand sheet sets these conditions:

• use only at lined landfills, at a full depth of six inches in place of soil;
• stockpile inside the disposal area and keep runoff and blowing sand from leaving it;
• accept no more sand than can be used in 45 days, and no more than 20 percent of the landfill’s average monthly waste stream;
• do not use it on exterior slopes or as intermediate cover;
• source the sand from within the landfill’s approved service area; and
• record the volume accepted and applied each day.

The landfill adds the cover to its operation plan and notifies DEQ’s Solid Waste Section. More than six inches counts as disposal.

For other uses, DEQ reviews each proposal. Check any destination and proposed use with DEQ before scheduling delivery. Get the receiving site’s specifications and written acceptance. If reuse is not cleared, arrange disposal that fits the waste determination.

Worker protection

• Silica: foundry sand is mostly crystalline silica. OSHA’s general industry standard, 29 CFR 1910.1053, sets a permissible exposure limit of 50 µg/m³ of respirable crystalline silica as an 8-hour average. Exposure assessment starts at the 25 µg/m³ action level.
• Construction use: crews placing sand as fill or subbase fall under the construction silica standard, 29 CFR 1926.1153.
• Lead: brass and bronze foundries that cast leaded alloys also follow OSHA’s lead standard, 29 CFR 1910.1025.
• Dust: control dust during shakeout, storage, and loading.

North Carolina Occupational Safety and Health (NC OSH) Division runs North Carolina’s OSHA-approved State Plan. For most employers, its standards apply in place of federal OSHA and must be at least as effective.

Storage and records

Store spent sand on a defined pad or in bins, control dust and runoff, and keep other foundry wastes out. To keep recovered material status, plan volumes so at least 75 percent of the sand stored on January 1 leaves by December 31.

Keep the waste determination, lab reports, DEQ approvals, and the receiving site’s acceptance together. Record tonnage shipped, dates, and destinations. Holders of a beneficial use determination file an annual usage report. Keep determination records for at least three years.

Before pickup

1. Identify the alloys cast, sand and binder systems, separate streams, monthly volume, and plant location.
2. Make the hazardous waste determination and complete the required tests.
3. Choose a destination and get its material specifications.
4. Confirm the sand meets the recovered material conditions, or get the DEQ beneficial use determination for that sand and use.
5. Get written acceptance and arrange pickup.

Common questions

Rules and guidance

• G.S. 130A-309.05: Regulated wastes; certain exclusions
• S.L. 2026-41, Section 12.18: Solid waste beneficial reuse clarification
• G.S. 130A-295.6: Sanitary landfill requirements
• NC DEQ: Approved Alternative Daily Cover Materials for Use at Sanitary Landfills
• 15A NCAC 13B .0562: Beneficial fill
• NC DEQ: Solid Waste Rules, Laws, and Regulations
• NC DEQ: Contact the Solid Waste Staff
• 15A NCAC 13A: Hazardous Waste Management
• 40 CFR 262.11: Hazardous waste determination
• 40 CFR 261.24: Toxicity characteristic
• EPA Method 1311: TCLP
• EPA: Beneficial Uses of Spent Foundry Sands
• EPA: Risk Assessment of Spent Foundry Sands in Soil-Related Applications
• 29 CFR 1910.1053: Respirable crystalline silica
• 29 CFR 1926.1153: Respirable crystalline silica in construction
• North Carolina Occupational Safety and Health (NC OSH) Division