Planning to reuse spent foundry sand in New Hampshire? This guide covers the rules that apply, the tests that decide how the sand can be managed, and what NHDES needs before a product made from the sand can be used.
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. New Hampshire handles this by certifying waste-derived products. A waste-derived product is made, in whole or in part, from materials recovered or diverted from the solid waste stream. NHDES certifies each product by rule or by 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.
New Hampshire’s waste-derived product rule
New Hampshire’s rule is Env-Sw 1500, Certification of Waste-Derived Products. No one may distribute or use a waste-derived product in New Hampshire unless it is certified. It must also be used as the certification allows.
A product is certified in one of two ways:
- By rule: Env-Sw 1503 lists products and groups of products that are certified automatically. Examples include salvaged materials, compost, and products that meet a published state or federal standard.
- By application: NHDES certifies other products that meet the criteria in Env-Sw 1504.
Ask NHDES whether your sand product fits a by-rule listing. If it does not, apply for certification. To certify a product by application, show that:
- it performs as well as a comparable product not made from waste, or meets an unfilled need;
- there is an identifiable user or buyer;
- written specifications define the waste and the product, and quality control keeps production in spec; and
- making, using, and disposing of it pose no greater risk than the comparable product or than disposing of the waste.
Every certified product has limits. It must not contain hazardous waste, asbestos, or other hazardous air pollutants. It must not contain waste that Env-Sw 900 lists as non-reusable.
A certified product that is actively managed and used under its certification is not a solid waste. The certification covers the product, not the waste used to make it. It does not exempt the facility that makes the product from the solid waste rules.
Casting sands as landfill cover
The landfill rules name casting sands. Under Env-Sw 806.03(e), casting sands may serve as alternate daily cover at a landfill. The landfill’s operating plan must approve the use, or the landfill must get a permit modification under Env-Sw 315. The cover material must:
- not be a hazardous waste;
- be physically and chemically consistent;
- contain no free liquids; and
- not cause operating problems, worsen leachate at lined landfills, contaminate surface water or groundwater, or harm people through skin contact or breathing.
This is a landfill operating approval held by the landfill. It is not a waste-derived product certification.
Applying to NHDES
- Who files: anyone may apply for a non-proprietary product. For a proprietary product, only the person with proprietary control may apply.
- How: submit form NHDES-S-05-020, Certify a Waste-Derived Product for Distribution and Use Application, on the NHDES online forms site (Env-Sw 1505.02).
- Waste data: describe the sand and give physical and chemical data from current, representative sampling. Include safety data sheets. NHDES may ask for samples.
- Signature: the applicant signs and affirms that the information is correct and complete.
- Review: NHDES decides whether the application is complete within 30 days of filing. You have one year to complete an incomplete application. A complete application gets a technical review against Env-Sw 1504.
- Decision: NHDES certifies the product with terms and conditions and adds it to its list, or denies it in writing.
- After approval: NHDES may suspend or revoke a certification after a hearing. One cause is a certification based on false, incomplete, or misleading information.
NHDES Solid Waste Management Bureau, permitting staff: (603) 271-2925, SolidWasteInfo@des.nh.gov. Products certified by application are listed on NHDES’s Certified Waste-Derived Products page.
Hazardous waste determination
New Hampshire writes its own hazardous waste rules, the Env-Hw rules, under RSA 147-A. They incorporate many federal provisions by reference. Under Env-Hw 101.04, references to 40 CFR mean the edition in effect on July 1, 2024.
New Hampshire’s corrosivity test reaches solids. Under Env-Hw 403.04, a non-aqueous waste can be corrosive (NH02). Mix it 50/50 by weight with distilled water. A pH of 2 or less, or 12.5 or more, makes it corrosive. The federal corrosivity test covers only aqueous and liquid wastes.
Under Env-Hw 502.01, 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.
New Hampshire 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, NHDES, 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.
A certification application needs current, representative test results for constituents reasonably thought to be in the sand that may pose a risk. NHDES will not deem an application complete until it receives any samples of the waste and product it requests.
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.
In New Hampshire, a product made from spent sand needs certification by rule or by application before it is distributed or used. NHDES keeps a list of all certified waste-derived products and provides it free on request. Check any destination and proposed use with NHDES before scheduling delivery.
A landfill may use casting sands as alternate daily cover when its operating plan or permit approves that use. Ask the landfill for its approval and acceptance criteria.
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.
Storage and records
Store spent sand on a defined pad or in bins, control dust and runoff, and keep other foundry wastes out. Distributors and users of a certified product must meet the environmental performance standards in Env-Sw 1002. A certified product that is abandoned or discarded becomes solid waste again.
Keep the waste determination, lab reports, the NHDES certification, and the receiving site’s acceptance together. Record tonnage shipped, dates, and destinations.
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.
- Confirm the product is certified by rule, or apply for NHDES certification. For landfill cover, confirm the landfill’s 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, NHDES certification, 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. NHDES still certifies each product in New Hampshire.
Can a landfill use our sand as daily cover?
Yes, if the landfill’s operating plan or a permit modification approves casting sands. The sand must not be hazardous, must be physically and chemically consistent, and must contain no free liquids. It must also meet the other cover criteria in Env-Sw 806.03(b).
Who can apply for certification?
Anyone may apply for a non-proprietary product. For a proprietary product, only the person with proprietary control can apply.
Can we rely on another company’s certification?
Only if your product is the certified product on the NHDES list and you follow its terms. A different sand or use needs its own review.
How long does NHDES take?
NHDES decides whether an application is complete within 30 days of filing. A complete application then gets a technical review against Env-Sw 1504.
Does certification cover the processing site?
No. Certification covers the product, not the facility that makes it. The facility still has to meet the solid waste rules.
Rules and guidance
- Env-Sw 1500: Certification of Waste-Derived Products
- NHDES: Certified Waste-Derived Products
- Env-Sw 800: Landfill Requirements
- Env-Sw 100: Solid Waste Program: Purpose, Applicability, and Definitions
- Env-Hw 100: Organizational Rules
- Env-Hw 400: Identification and Listing of Hazardous Wastes
- Env-Hw 500: Requirements for Hazardous Waste Generators
- 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