172

Metal dust and machining waste

Waste Family

Inorganics

Waste Code

172

Regulation

22 CCR App. XII

Where code 172 applies

California waste codes come from 22 CCR Division 4.5, Chapter 11, Appendix XII. A California code is required on the hazardous waste manifest for every load generated in or shipped into California — even for wastes that are hazardous only under California law and carry no federal code.

RCRA-regulated streams list a federal RCRA waste code on the manifest alongside code 172.

Related inorganics codes

Alkaline and aqueous solutions, surplus inorganic chemicals, asbestos waste, spent catalysts, metal sludges, dusts and other inorganic solids. Metal content and pH drive the code choice.

121Alkaline solution (pH <= 12.5) with metals (antimony, arsenic, barium, beryllium, cadmium, chromium, cobalt, copper, lead, mercury, molybdenum, nickel, selenium, silver, thallium, vanadium, zinc)122Alkaline solution without metals (pH > 12.5)123Unspecified alkaline solution 131Aqueous solution (2 < pH < 12.5) containing reactive anions (azide, bromate, chlorate, cyanide, fluoride, hypochlorite, nitrite, perchlorate, sulfide)132Aqueous solution with metals at restricted levels 133Aqueous solution with 10% or more total organic residues 134Aqueous solution with less than 10% total organic residues 135Unspecified aqueous solution

All California waste codes

Where can a 172 stream go?

Recognized recovery routes for this waste family, ranked by typical recovery tier. Which route fits depends on your specific stream — composition, volume and region.

Metals recovery (HTMR / hydrometallurgical)

Medium recovery

Metal-bearing streams route to high temperature metals recovery or hydrometallurgical processing, where the contained metals are extracted and returned to commerce as secondary raw material.

40 CFR 268.42 Table 1 — HTMR technology standard

Acid / alkali regeneration

Medium recovery

Spent acids and caustics are regeneration candidates: spent pickling and etching liquors can be processed for acid recovery or metal-salt by-products, depending on free-acid strength and dissolved metal load.

40 CFR 261.1(c)(4) — reclamation

On-site elementary neutralization

Low recovery

Streams hazardous only for corrosivity can be treated in an elementary neutralization unit — a recognized unit type that manages the characteristic without a full treatment permit.

40 CFR 260.10 — definitions

These are the typical routes for inorganics. Your stream's actual options depend on its composition and where it sits.

Get the ranked options for your stream

Get buyer contacts for California waste code 172

Leave your work email. Our industrial desk sends verified company contacts with location-specific pricing and contract minimums for metal dust and machining waste — not generic benchmarks.

Reviewed by our industrial desk within 1 business day.