Planning to reuse spent foundry sand in Wyoming? 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 Wyoming, beneficial use must be conducted in a manner DEQ approves.
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.
Wyoming’s beneficial use exemption
Wyoming requires all solid waste to be disposed of, treated, or recycled at designated facilities. Both DEQ’s Solid and Hazardous Waste Division and the local governing body (county, city, or town) must approve the facility.
Wyoming’s Solid Waste Rules, Chapter 1, Section 1(f)(xv), let DEQ exempt beneficial use from permitting. Beneficial use means reusing wastes in a way that is beneficial, protects human health and the environment, and is conducted in a manner DEQ approves.
DEQ may require you to show that an activity qualifies for an exemption. You must allow DEQ inspectors to verify that information. DEQ issues no exemption unless the facility owner gives written permission for inspections, sampling, and records access (Chapter 1, Section 1(g)).
Without an exemption, a permit is required to locate, build, operate, or close a solid waste management facility. The clean fill exemption covers only uncontaminated natural soil and rock, hardened asphalt rubble, bricks, and concrete rubble.
Working with DEQ
- Who decides: DEQ’s Solid and Hazardous Waste Division approves how a beneficial use is conducted.
- What to provide: information showing the reuse is beneficial and protects human health and the environment. Include written permission for DEQ inspections, sampling, and records access.
- How to submit: the Division accepts electronic submittal of work plans, reports, general correspondence, and solid waste permit applications.
- Facilities: if a facility will treat, store, or recycle the sand, confirm it holds both Division and local approval for that waste.
Wyoming DEQ: (307) 777-7937.
Hazardous waste determination
Wyoming adopts the federal hazardous waste rules (40 CFR Parts 124, 260–268, 270, 273, and 279, through July 7, 2020) by reference in Hazardous Waste Rules, Chapter 1, Section 2.
Wyoming adds a sham recycling test for hazardous waste (Chapter 1, Section 261(b)). DEQ may find that a proposed hazardous waste recycling activity is sham recycling. Factors include hazardous constituents or characteristics that the replaced raw material lacks, use beyond the amount of raw material needed, and whether the material has value with a guaranteed market for the end product. Sham recycling is treated as treatment or disposal and needs a hazardous waste permit.
Under 40 CFR 262.11, the foundry must decide whether its spent sand is hazardous:
- Make the determination at the point of generation, before mixing or dilution. Repeat it if the waste may have changed.
- Check whether the waste is excluded from the hazardous waste rules.
- Check whether it matches a listed hazardous waste.
- 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:
| Contaminant | EPA waste code | Limit (mg/L) |
|---|---|---|
| Arsenic | D004 | 5.0 |
| Barium | D005 | 100.0 |
| Cadmium | D006 | 1.0 |
| Chromium | D007 | 5.0 |
| Lead | D008 | 5.0 |
| Mercury | D009 | 0.2 |
| Selenium | D010 | 1.0 |
| Silver | D011 | 5.0 |
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.
Wyoming adopts 40 CFR Part 261, including these limits, by reference in its Hazardous Waste Rules, Chapter 1, Section 261. DEQ may ask for the information it needs to confirm a beneficial use qualifies for an exemption.
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 decides beneficial use case by case. Check any destination and proposed use with DEQ before scheduling delivery.
When you talk to DEQ, explain how the use is beneficial and how it protects health and the environment. If a facility will process or store the sand first, confirm it is a designated facility with DEQ and local approval. 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.
Wyoming Occupational Safety and Health Administration (Wyoming OSHA) runs Wyoming’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. Wyoming prohibits speculative accumulation of solid waste at a facility intended for use as a solid waste management facility without a permit (Chapter 1, Section 1(e)(vi)).
Keep the waste determination, lab reports, DEQ approvals, and the receiving site’s acceptance together. Record tonnage shipped, dates, and destinations. Keep determination records for at least three years.
Before pickup
- Identify the alloys cast, sand and binder systems, separate streams, monthly volume, and plant location.
- Make the hazardous waste determination and complete the required tests.
- Choose a destination and get its material specifications.
- Get DEQ’s approval for the beneficial use, or confirm the receiving facility holds DEQ and local approval.
- Get written acceptance and arrange pickup.
Common questions
Is a passing TCLP test enough?
No. It answers a toxicity question for the substances tested. The full waste determination, DEQ approval, and the receiving site’s specifications still apply.
Does EPA’s risk assessment approve our sand?
No. It supports three soil-related uses for silica-based sand from iron, steel, and aluminum foundries. DEQ still decides each use in Wyoming.
Does Wyoming have a beneficial use exemption?
Yes. DEQ may exempt reuse that is beneficial, protects human health and the environment, and is conducted in a manner DEQ approves.
Can spent sand be used as clean fill?
No. Wyoming defines clean fill as only uncontaminated natural soil and rock, hardened asphalt rubble, bricks, and concrete rubble.
Does the receiving facility need approval?
Yes. Solid waste must be treated, recycled, or disposed of at designated facilities approved by both DEQ and the local governing body.
Can hazardous spent sand be recycled?
Only through legitimate recycling. DEQ may find that a proposed hazardous waste recycling activity is sham recycling, which then needs a hazardous waste permit.
Rules and guidance
- Wyoming DEQ: Solid Waste
- Wyoming Solid Waste Rules, Chapter 1: General Provisions
- Wyoming Hazardous Waste Rules, Chapter 1: General Provisions
- 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
- Wyoming Occupational Safety and Health Administration (Wyoming OSHA)