Foundry Sand Reuse in Indiana

Planning to reuse spent foundry sand in Indiana? This guide covers the rules that apply, the tests that decide how the sand can be managed, and what IDEM 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. Indiana’s rules call this “legitimate use.” IDEM also issues waste classifications (Type I to IV). Type III foundry sand may be used for the uses listed in IC 13-19-3-7 without a permit.

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.

Indiana’s foundry sand law

Indiana has a statute written for foundry sand, IC 13-19-3-7. A permit is not required to use foundry sand that meets Type III criteria under 329 IAC 10-9 for the activities it lists. IDEM says no approval is needed for these uses once the waste classification is issued, provided IDEM guidance for the use is followed.

What counts as foundry sand

IDEM treats foundry sand as molding sand and core sand. Baghouse dust from sand handling systems may be used under the statute if it is only fine sand particles. Baghouse dust from furnace emissions, grinding, or shot blast operations may not.

For land application and soil amendment, IDEM guidance excludes refractory, slag, grinding dust or sludge, scrubber sludge, shot blast dust, baghouse dust other than from molding sand handling, unused cores, metal scrap, pattern shop waste, solvents, and maintenance waste.

Type III classification

The generator must get a Type III waste classification from IDEM and keep it current as long as the sand is used. IDEM certifies the classification in writing under 329 IAC 10-9-4. Sand with a Type IV classification is excluded from the solid waste rules under 329 IAC 10-3-4, with placement limits, and is also eligible for the statute’s uses.

IDEM compares the 90% upper confidence limit of your results with these Type III limits:

Uses listed in IC 13-19-3-7

IDEM’s nonrule policy Waste-0028 lists the uses and adds conditions:

1. Landfill daily cover, under the landfill’s permits. A landfill not yet approved must get a permit modification first.
2. Protective cover for a landfill leachate system, under the landfill’s permits and 329 IAC 10-17-11 and 10-17-12.
3. Capped embankments for ground and sight barriers under 10,000 cubic yards, or embankments for airports, bridges, or overpasses. Cover side slopes with at least one foot of soil that supports vegetation. A larger barrier needs IDEM approval.
4. Land application or soil amendment, when it does not include operating a landfill. Follow nonrule policy Waste-0040, which sets total metals limits and application rates.
5. Structural fill base capped by clay, asphalt, or concrete for roads, road shoulders, parking lots, floor slabs, utility trenches, bridge abutments, tanks and vaults, construction or architectural fill, and similar uses. Construct roads, parking lots, and floor slabs of concrete or asphalt. Do not leave the sand uncovered. Construction or architectural fill does not include land reclamation.
6. Raw material in another product, such as flowable fill, concrete, asphalt, brick, block, portland cement, glass, roofing, rock wool, plastics, fiberglass, mineral wool, lightweight aggregate, paint, or plaster. Use at another foundry is allowed. Other products must be chemically and physically similar to a listed one, or need IDEM approval.

Other uses: legitimate use approval

For uses the statute does not list, or for Type I or Type II sand and other foundry wastes, IDEM can grant case-by-case approval under 329 IAC 10-3-1(16). The commissioner must find the use is legitimate and does not threaten public health or the environment. IDEM cannot approve general filling or other disposal practices as a legitimate use.

Applying to IDEM

• Who files: the generating foundry requests the waste classification from IDEM’s Industrial Waste Compliance Section. The foundry must keep the classification current.
• Waste information first: complete the waste information required by 329 IAC 10-7.2 and submit it with the request.
• Request content: include a narrative of the process, the raw materials, the waste determination documents, and complete sampling and lab records with QA/QC data. Add the signed certification statement required by 329 IAC 10-9-4(j).
• Review: IDEM staff inspect to verify the request and notify the foundry of the classification in writing.
• Term: initial classifications usually run two to five years, depending on process variability, raw materials, compliance, and where the sand goes.
• Renewal: request renewal, with a sampling plan or full data, at least 90 days before expiration. To ask IDEM to reduce or waive testing, apply at least 120 days before. If renewal is late, the classification expires, and IDEM grants no extensions.
• Legitimate use requests: file State Form 52954 with supporting documents. Each form covers one waste stream, one use, and one location. The approval does not replace any other local, state, or federal permit.
• Landfill uses: any use at a permitted landfill may require a modification to the landfill’s permit.

IDEM Office of Land Quality: (317) 234-6923. Legitimate use requests: legitimateuse@idem.IN.gov, Industrial Waste Compliance Section, 100 N. Senate Ave., Mail Code 66-20-1, Indianapolis, IN 46204-2251.

Hazardous waste determination

Indiana has adopted most of the federal hazardous waste rules (40 CFR Parts 260–270 and 273) in 329 IAC 3.1, as IDEM’s hazardous waste program explains. State exceptions and additions are noted in those rules.

Indiana adds a solid waste step. Under 329 IAC 10-7.2, generators must keep waste information on each stream. It covers hazardous waste, PCBs, asbestos, pesticide residues, heat generation, and any other risk. Only nonhazardous waste without PCBs, asbestos, or FIFRA-regulated pesticide residues may be evaluated for a waste classification.

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, IDEM, 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.

For a classification, test each waste stream on its own, with at least three sample sets from separate generating events. Metals are tested by TCLP. IDEM may accept totals instead when every 90% upper confidence limit is below 20 times the TCLP threshold. Land application and soil amendment also need a total metals analysis under Waste-0040.

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.

With a current Type III classification, the uses listed in IC 13-19-3-7 need no individual IDEM approval when you follow IDEM’s guidance. For structural fill, place the sand in compacted lifts under a quality plan or design specifications. Cover the finished project with clay-type soil and vegetation, normally at least 12 inches.

For land application, keep metals under the ceiling limits and within the lifetime and annual rates in Waste-0040. A soil amendment product must meet that policy’s product limits. Do not store or apply sand in karst areas, wetlands, critical habitats, or floodways unless special arrangements protect them.

IDEM decides any other use case by case. 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.

Indiana Occupational Safety and Health Administration (IOSHA) runs Indiana’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

IDEM’s nonrule policy Waste-0027 covers storage facilities for Type III sand. It does not cover storage at the generating plant or short-term storage at job sites. Those sites must still meet the storage definition and the prohibited acts rules.

• Notice: a facility storing sand more than 24 hours should notify IDEM in writing before accepting it. Name the owner, location, sand source, design, operating plan, and turnover rate. Show a market and use within six months.
• Six-month presumption: storage over six months is presumed to be disposal (329 IAC 10-2-181). IDEM allows longer storage after notice, if the sand is stored soundly and will be used under state rules.
• Pad and setbacks: place piles on a low-permeability pad, at least two feet above the seasonal high water table. IDEM guidance calls for 600 feet from a potable well (200 feet with a DNR well record) and 50 feet from the property line.
• Runoff and dust: divert run-on, manage runoff, and control erosion, dust, and odors. Any discharge to surface water needs an NPDES permit.
• No mixing: never mix the sand with hazardous waste, other industrial waste, or municipal solid waste. Mix with other aggregate only to meet a product specification.
• Speculative accumulation: not permitted. IDEM will require unused sand to be removed and disposed of at a permitted facility.

Keep the waste classification, lab reports, IDEM approvals, and the receiving site’s acceptance together. Keep bills of lading, receipts, or contracts showing volumes and end uses. 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 329 IAC 10-7.2 waste information.
3. Get or renew the IDEM Type III waste classification for each sand stream.
4. Choose a destination and use. Confirm it is listed in IC 13-19-3-7, or file for a legitimate use approval.
5. Get written acceptance and arrange pickup.

Common questions

Rules and guidance

• IC 13-19-3: Solid and hazardous waste powers, including § 13-19-3-7 (foundry sand)
• IDEM: Foundry Waste Classification Guidelines
• IDEM Waste-0028: Use of Foundry Sands in Accordance with House Enrolled Act 1541
• IDEM Waste-0027: Storage of Type III Foundry Sands Prior to Legitimate Use
• IDEM Waste-0040: Use of Foundry Sand in Land Application and as a Soil Amendment
• IDEM Fact Sheet: Foundry Sand and Other Solid Waste as Structural Fill
• IDEM: Industrial Solid Waste
• IDEM: About Waste and How We Manage It
• IDEM Forms: Legitimate Use Application Checklist (State Form 52954)
• IDEM: Effective Nonrule Policies
• IDEM: Hazardous Waste
• 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
• Indiana Occupational Safety and Health Administration (IOSHA)