Foundry Sand Reuse in Connecticut

Planning to reuse spent foundry sand in Connecticut? This guide covers the rules that apply, the tests that decide how the sand can be managed, and what DEEP 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. Connecticut law calls it “casting sand”: waste sand from the casting of metals that is not hazardous waste.

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 Connecticut, “beneficial use” means using a solid waste in a manufacturing process to make a product, or as an effective substitute for a commercial product. DEEP approves it through a Beneficial Use Determination (BUD) or a general 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.

Connecticut’s casting sand and beneficial use laws

Connecticut’s solid waste laws are in Chapter 446d of the General Statutes. Two sections name casting sand directly.

Casting sand at permitted disposal areas

Under CGS § 22a-209d, DEEP may not prohibit the use of waste sand from metal casting at a solid waste disposal area permitted under § 22a-208a. The sand may be used as cover, road base, fill, or for other purposes there. Two conditions apply:

1. toxic materials in the sand must be below the hazardous waste level under the federal Resource Conservation and Recovery Act; and
2. the person disposing of the sand must certify, to DEEP’s satisfaction, that the sand is not hazardous.

Large-scale fill pilot program

Under CGS § 22a-209f(c), casting sand is one of the “beneficially reclaimed materials” DEEP may allow as fill in a pilot program. The program’s purpose is fill with an engineering need, to reclaim or redevelop impaired or underused land. Its terms are strict:

• Number: DEEP may issue no more than four authorizations.
• Size: each covers one location and at least 100,000 cubic yards of fill.
• Location: the site must be in a GB or GC groundwater area served by a public drinking water supply, and outside any aquifer protection area.
• Exclusions: material containing asbestos, PCBs, persistent bioaccumulative toxins, or hazardous waste does not qualify.
• Monitoring: the application includes a plan to monitor state waters during filling and for at least 30 years after.
• Security: DEEP requires a letter of credit to cover closure and post-closure monitoring.

Beneficial Use Determinations

Under § 22a-209f(b), DEEP may approve the beneficial use of solid waste in a manufacturing process to make a product, or as an effective substitute for a commercial product. DEEP may approve it only when:

1. the approval does not allow an activity already covered by an individual or general permit;
2. the approval is consistent with the federal Resource Conservation and Recovery Act; and
3. DEEP finds the waste can be reused without harming or threatening public health, safety, or the environment.

Before issuing or renewing a BUD, DEEP posts a notice of intent on its website for 30 days of public comment. Each approval defines the covered activity and may set conditions, such as operating practices, reporting, and a term. DEEP may suspend, revoke, or modify an approval.

Applying to DEEP

• Who files a BUD: a generator that provides solid waste to others for beneficial use. A facility that accepts and processes the waste also files. An already permitted facility requests a permit modification instead.
• How: submit DEEP’s BUD application form with supporting documents and the fee. Use one application form for each approval.
• Content: describe the waste, how it is generated, annual tons, and past management. Explain the proposed use, testing and monitoring, chemical constituents, mixing ratios, processing, and the market for the final product.
• BUD fees: $1,000 up to 120 tons a year, $2,500 from 120 to 1,200 tons, and $5,000 above 1,200 tons. Renewals and modifications cost half. Fees are not refundable, and municipalities pay none.
• Start date and term: the activity is authorized only on or after the date DEEP issues written approval. A BUD approval lasts ten years. Renew at least 180 days before it expires.
• Pilot program: the site owner or operator applies on DEEP’s large-scale filling pilot form before operations begin. DEEP recommends a pre-application meeting. The application fee is $25,000 and is not refundable.
• Landfill disposal: casting sand is a “special waste” under RCSA § 22a-209-1. Anyone disposing of special waste at a landfill or resources recovery facility applies for a DEEP Special Waste Disposal Authorization.

DEEP Solid Waste Permitting: 860-424-3366.

Hazardous waste determination

Connecticut adopts the federal hazardous waste rules by reference, with state changes, in RCSA §§ 22a-449(c)-100 to 22a-449(c)-119. Section 22a-449(c)-101 adopts 40 CFR Part 261, and 22a-449(c)-102 adopts Part 262. These references use the CFR as revised July 1, 2000.

Connecticut requires generators to repeat the determination at least once every 12 months, and whenever the generating process changes. A determination based on knowledge must show clearly how that knowledge was applied. Connecticut also regulates some wastes that are not RCRA hazardous, called Connecticut-Regulated Wastes, under CGS § 22a-454.

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

1. Check whether the waste is excluded from the hazardous waste rules.
2. Check whether it matches a listed hazardous waste.
3. Check for hazardous characteristics, including toxicity. Test the waste, or apply knowledge of the materials and processes used.

Keep test results, waste analyses, and other determinations for at least three years after the waste was last sent for treatment, storage, or disposal (40 CFR 262.40(c)).

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, DEEP, 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.

Casting sand used at a permitted disposal area needs a certification, to DEEP’s satisfaction, that it is not hazardous. For a BUD, DEEP reviews the sand’s chemical constituents, any characterization studies, and the testing or monitoring you propose.

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.

Connecticut names three routes for casting sand:

• Permitted disposal areas: cover, road base, fill, or other uses at a solid waste disposal area permitted under § 22a-208a, with the nonhazardous certification.
• Pilot fill sites: fill at one of no more than four DEEP-authorized large-scale sites under § 22a-209f(c).
• BUD approval: an ingredient in a manufacturing process, or an effective substitute for a commercial product. DEEP asks for proof of a market, such as contracts or letters of commitment.

Check any destination and proposed use with DEEP 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.

CONN-OSHA covers state and local government workers in Connecticut. Federal OSHA covers private employers.

Storage and records

Store spent sand on a defined pad or in bins, control dust and runoff, and keep other foundry wastes out. Follow the storage conditions in the BUD approval or other DEEP authorization.

Keep the waste determination, the yearly redeterminations, lab reports, nonhazardous certifications, DEEP approvals, and the receiving site’s acceptance together. Record tonnage shipped, dates, and destinations.

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 route with DEEP: the permitted disposal area and nonhazardous certification, a pilot authorization, or a BUD approval.
5. Get written acceptance and arrange pickup.

Common questions

Rules and guidance

• CGS § 22a-209d: Casting sand at permitted disposal areas
• CGS § 22a-209f: Beneficial use of solid waste
• Connecticut DEEP: Beneficial Use of Solid Waste
• DEEP: Beneficial Use Determination fact sheet
• DEEP: Guidelines for BUD authorizations
• DEEP: Large-scale filling pilot program application instructions
• RCSA § 22a-209-1: Solid waste definitions
• RCSA § 22a-449(c)-101: Identification and listing of hazardous waste
• DEEP: Connecticut-Regulated 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
• CONN-OSHA