Foundry Sand Reuse in Michigan

Planning to reuse spent foundry sand in Michigan? This guide covers the rules that apply, the tests that decide how the sand can be managed, and what Part 115 and EGLE require 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 Michigan, Part 115 calls a listed material used for a listed purpose a “beneficial use by-product.” Foundry sand from ferrous or aluminum foundries is on that list. EGLE can approve other materials and uses.

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.

Michigan’s beneficial use law

Michigan’s beneficial use rules are in Part 115 of the Natural Resources and Environmental Protection Act, MCL 324.11502 and 324.11551 to 324.11553. Part 115 defines foundry sand as silica sand used in metal casting, including binding material or carbonaceous additives, from ferrous or nonferrous foundries.

The foundry sand listing

Under MCL 324.11502(12)(g), foundry sand from ferrous or aluminum foundries is a beneficial use by-product for beneficial uses 1 to 5. It qualifies only while it is stored for, or used in, one of those uses and meets MCL 324.11551(1). The five uses are:

1. Beneficial use 1: aggregate, road material, or building material that in its final use is bonded or encapsulated by cement, lime, or asphalt.
2. Beneficial use 2: construction fill at nonresidential property, road base, soil stabilizer, or road shoulder material. Place it at least 4 feet above the seasonal groundwater table and keep it out of contact with surface water. Cover it with concrete, asphalt pavement, or other material EGLE approves. Road shoulders must be sloped and may instead be covered with 6 inches of gravel. Layers may not exceed 4 feet thick, except where existing topography varies. The 4-foot limit does not apply to construction fill under a building or other structure.
3. Beneficial use 3: land application as a fertilizer or soil conditioner under Part 85, or as a liming material under 1955 PA 162. Apply it at an agronomic rate consistent with generally accepted agricultural and management practices. The use must not violate air quality law, create a nuisance, make groundwater unfit for a protected use, or violate a surface water quality standard.
4. Beneficial use 4: stabilizing or treating waste for disposal at a licensed facility, treating wastewater or wastewater sludge, or remediating contaminants in a response activity or corrective action. It also covers construction material at a licensed landfill, and alternate daily cover at a licensed landfill under an approved operational plan.
5. Beneficial use 5: blended with inert materials or compost to manufacture soil.

Every use must meet MCL 324.11551(1). The sand cannot be a hazardous waste or be mixed with one. Store it so it stays useful, controls wind dispersal, stays within the storage area, and does not harm groundwater or surface water. Transport it without leaks, spills, or wind dispersal. Use it for a legitimate purpose, not as a way to discard it, and follow accepted engineering, industrial, or commercial standards for that use.

Three uses add limits for foundry sand:

• Beneficial use 2: leachate must not exceed 0.2 mg/L arsenic, 0.08 mg/L lead, or 2.0 mg/L nickel. The generator chooses EPA Method 1311 or 1312, or ASTM method 3987.
• Beneficial use 3: the total amount applied to an area of land over time may not exceed these loads, in pounds per acre: arsenic 37, cadmium 35, copper 1,335, lead 267, mercury 15, nickel 374, selenium 89, and zinc 2,492. The material must be registered or licensed each year under Part 85 or 1955 PA 162. The Michigan Department of Agriculture and Rural Development (MDARD) oversees this use.
• Beneficial use 5: representative sampling must show the sand does not exceed the limits below. Use a totals analysis, a leachate analysis, or both. Leachate methods are EPA Method 1311 or 1312, ASTM method 3987, or another protocol EGLE approves.

EGLE approvals

For sand or uses outside the listing, ask EGLE for approval under MCL 324.11553. Examples are sand from nonferrous foundries other than aluminum, or beneficial use 2 at residential property or thicker than 4 feet. EGLE must approve a material for a specified use as a beneficial use by-product when:

1. it is an industrial or commercial material generated, or able to be generated, in high volumes;
2. the use serves a legitimate purpose other than discarding it;
3. a market exists, or could reasonably be created;
4. the material and use meet consumer protection and product safety laws; and
5. its hazardous substances pose no direct contact hazard, its leachate stays within groundwater drinking water and surface water criteria, and its emissions meet air law and create no nuisance.

EGLE may also approve a material that fails the last test if the material and use still protect health and the environment.

Notices, reports, and EGLE approvals

• Listed uses: Part 115 sets the conditions directly. Meet MCL 324.11551 for the chosen use, and file the notices and reports in MCL 324.11552.
• Large fills: send EGLE written notice before foundry sand is first used as beneficial use 2 construction fill at a site, when the amount will exceed 5,000 cubic yards. The generator files, or the broker if the generator transferred the sand to one.
• Annual report: a generator or broker of more than 1,000 cubic yards used for beneficial use 1, 2, or 4 reports by October 30. The report covers October 1 to September 30. It lists the business contact, the types and amounts generated, brokered, and stored, and the amounts shipped off site with their uses. You may mark the amounts and uses as confidential business information.
• Who can ask for approval: any person may ask EGLE to approve a material, a use, or both under MCL 324.11553.
• What to send: a written request describing the material and the process that generates it, and the proposed use. Include analyses of representative samples for any hazardous substances you know or suspect could be present.
• Test methods: use EPA SW-846, Standard Methods, a peer-reviewed standard such as ASTM, or a method EGLE or EPA approves.
• Review time: EGLE approves or denies in writing within 150 days, unless you agree to an extension. If information is missing, EGLE tells you within 60 days, and the clock stops until you send it. A request not decided within 150 days is considered approved.
• Conditions: EGLE may attach conditions reasonably necessary for the use. An approval must state its conditions, and a denial must state its reasons.

EGLE Beneficial Use Program: EGLE-MMD-BeneficialUseProgram@Michigan.gov.

Hazardous waste determination

Michigan runs its own hazardous waste program under Part 111 of the Natural Resources and Environmental Protection Act. Its Part 111 rules (R 299.9101 to R 299.11107) adopt selected federal provisions by reference in R 299.11003.

Michigan adds a state-only severe toxicity characteristic. A waste is hazardous if it contains 1 part per million or more of a substance in table 202 (R 299.9212(5)). Table 202 lists aflatoxin and certain dioxins and furans.

Under R 299.9302, 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.

Michigan requires generators to keep determination records for at least 3 years.

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, EGLE, 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 listed use, the hazardous waste and beneficial use 2 checks rest on the initial generator’s analysis of a representative sample. Beneficial use 5 needs its own totals or leachate testing against the limits above.

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.

Part 115 lists ferrous and aluminum foundry sand for beneficial uses 1 to 5. Match each destination to one use and meet that use’s conditions. For example, the sand might be asphalt or concrete aggregate (use 1), covered road base (use 2), landfill daily cover under the landfill’s approved plan (use 4), or a manufactured soil blend (use 5). Land application (use 3) also needs MDARD registration or licensing.

For other foundry sand or other uses, get EGLE approval under MCL 324.11553 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.

Michigan Occupational Safety and Health Administration (MIOSHA) runs Michigan’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. Do not store sand at the site of generation or use for more than 3 years. The exception is when at least 75% of the amount stored at the start of a 3-year period ships off site for use within that period.

Keep the waste determination, lab reports, EGLE approvals, and the receiving site’s acceptance together. Record tonnage shipped, dates, and destinations. The initial generator keeps by-product test results for at least 10 years after the sand leaves the site. A contractor who places beneficial use 2 material must tell the property owner the date and location of use.

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 Part 115 use and its conditions, or get EGLE approval under MCL 324.11553. File any required notice.
5. Get written acceptance and arrange pickup.

Common questions

Rules and guidance

• EGLE: Beneficial Use
• Part 115, Solid Waste Management (MCL 324.11501 and following)
• Part 111 Hazardous Waste Management rules (R 299.9101 to R 299.11107)
• 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
• Michigan Occupational Safety and Health Administration (MIOSHA)