Foundry Sand Reuse in Texas | Foundry Recycling Services

Planning to reuse spent foundry sand in Texas? This guide covers the rules that apply, the tests that decide how the sand can be managed, and what TCEQ 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. Texas treats it as recycling under 30 TAC Chapter 335. Some recycled materials, including qualifying iron and steel foundry sand, are not solid waste at all.

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.

Texas’s foundry sand and recycling rules

Iron and steel foundry sand

Texas’s definition of solid waste has its own foundry sand provision, 30 TAC § 335.1(160)(N). Foundry sand from the iron and steel casting industry is not considered solid waste when the sand is:

an intended output or result of an iron or steel casting process that makes cast iron and steel products;
introduced into the stream of commerce;
managed as an item of commercial value, which can include a controlled use in a manner constituting disposal; and
not managed as discarded material.

TCEQ added this provision in 2022. It formalized a 1995 TCEQ determination that iron and steel foundry sand reused as a substitute material is a co-product. The provision names sand from iron and steel casting only. Sand from other alloys follows the general rules below.

Anyone who claims a material is not solid waste must show a known market or disposition for it. They must also show they meet the exclusion’s terms, with documents such as contracts showing another person uses the material in production (§ 335.1(160)(I)).

Other recycling exclusions

Under § 335.1(160)(F), a material is not solid waste when it is shown to be recycled by being:

used as an ingredient in an industrial process to make a product, without first being reclaimed;
used as an effective substitute for a commercial product; or
returned to the original process that generated it, as a substitute for feedstock, without first being reclaimed or land disposed.

These exclusions do not cover material used in a manner constituting disposal or used to make products applied to the land. They also do not cover material burned for energy or accumulated speculatively (§ 335.1(160)(G)).

Land uses have their own test. Under § 335.1(160)(H), nonhazardous material applied to the land, or used in products applied to the land, is not solid waste only if it meets every listed criterion. These include:

a legitimate market for the material and its products;
meeting the specifications of the product it replaces, without treatment or reclamation;
Class 3 status, except that arsenic, cadmium, chromium, lead, mercury, nickel, and selenium may be Class 2 within the metal limits of 30 TAC § 312.43(b)(3), Table 3; and
recycling or transfer for recycling of at least 75 percent of each year’s production.

Recycling industrial waste

Sand that is still a solid waste can be recycled as nonhazardous industrial waste. Legitimate recycling under § 335.24(h) needs no waste permit. It still needs advance notice to TCEQ under § 335.6.

Notifying TCEQ

Excluded sand: material that is not solid waste needs no recycling notice. It remains subject to the general prohibitions of 30 TAC § 335.4.
Who files: for recycling industrial waste, the generator files Form TCEQ-0525. The receiving recycler files Form TCEQ-0524.
When: at least 90 days before recycling begins. Recycling may start after 90 days if TCEQ has not asked for more information, or once TCEQ acknowledges the notice (§ 335.6(h)).
What to include: the waste’s type, classification, and Texas waste code; how it is stored before recycling; and the nature of the recycling.
How: email the form to ihwper@tceq.texas.gov or submit it through STEERS.
Changes: notify TCEQ again after substantial changes in the waste’s composition, the recycling method, or the end products.

TCEQ Industrial and Hazardous Waste Permits Section: 512-239-2335, ihwper@tceq.texas.gov.

Hazardous waste determination

Texas adopts the federal hazardous waste rules into 30 TAC Chapter 335, with or without changes. For example, § 335.53 adopts the federal determination recordkeeping rules in 40 CFR 262.11(e)–(g).

Texas adds its own classes for nonhazardous industrial waste. Under § 335.503, the generator classifies each waste at the point of generation as hazardous, Class 1, Class 2, or Class 3. A nonhazardous waste is Class 1 if its TCLP extract meets or exceeds a level in the Texas Class 1 table (§ 335.505). A site that generates more than 100 kilograms of Class 1 waste in a month must register with TCEQ (§ 335.6(c)).

Under 30 TAC § 335.504, 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.

Texas 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, TCEQ, 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:

TCLP regulatory levels, RCRA metals
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.

The Texas Class 1 limits are lower for some metals: lead 1.5 mg/L, arsenic 1.8 mg/L, cadmium 0.5 mg/L, and beryllium 0.08 mg/L (TCEQ RG-022, Appendix B). A Class 2 or Class 3 classification needs supporting analytical data or process knowledge (§ 335.503(a)(4)).

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.

Texas relies on the rule terms and advance notice, not a reuse permit. For iron and steel sand, document how the sale meets each condition of § 335.1(160)(N). For other sand, check any destination and proposed use with TCEQ before scheduling delivery.

Describe the use with the categories in § 335.1. Is the sand a manufacturing ingredient, a substitute for a commercial product, or a land use? Get the receiving site’s specifications, written acceptance, and evidence of a legitimate market. If reuse is not cleared, arrange disposal that fits the waste determination and Texas waste class.

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. Material is accumulated speculatively unless it can feasibly be recycled. At least 75 percent of what was on hand on January 1 must be recycled or transferred for recycling that calendar year (§ 335.17(a)(8)). Label each storage unit with the date accumulation began.

Keep the waste determination and class, lab reports, TCEQ notices, sales contracts, and the receiving site’s acceptance together. Record tonnage shipped, dates, and destinations. Texas requires generators to keep waste documentation for at least three years after the waste is no longer generated or stored, or until site closure (§ 335.513(c)).

Before pickup

Identify the alloys cast, sand and binder systems, separate streams, monthly volume, and plant location.
Make the hazardous waste determination, assign the Texas waste class, and complete the required tests.
Choose a destination and get its material specifications.
Document how iron or steel sand meets § 335.1(160)(N), or file Form TCEQ-0525 at least 90 days before recycling begins.
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, the Texas waste class, the recycling rules, 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. Texas rules still decide each use in Texas.

Does iron or steel foundry sand need a recycling notice?

Not if it meets every condition of § 335.1(160)(N). Material that is not solid waste needs no notice. Keep records that show a known market and that the sand is managed as a commodity.

Does the foundry sand provision cover aluminum or brass sand?

The provision names foundry sand from the iron and steel casting industry. Sand from other alloys can use the general recycling exclusions in § 335.1 or the notice route for recycling industrial waste.

Who notifies TCEQ?

For recycling industrial waste, both sides. The generator files Form TCEQ-0525 and the receiving recycler files Form TCEQ-0524, each at least 90 days before recycling begins.

How long can spent sand be stockpiled?

Recycle or transfer at least 75 percent of the material on hand at the start of each calendar year. Otherwise it is accumulated speculatively and stays a solid waste.