Before anything else — before a manifest gets created, before an LDR notice gets filed — someone has to determine whether a given waste is a RCRA hazardous waste at all, and if so, which EPA waste code(s) apply. Get this step wrong and everything downstream inherits the mistake: the wrong codes on a manifest, the wrong (or missing) LDR notice, the wrong treatment at the disposal facility.
Two different ways a waste can be hazardous
There are two entirely separate paths to a waste being regulated, and a single waste can qualify under both:
- Listed waste — EPA has specifically named this waste (or its source) as hazardous, regardless of whether it tests as dangerous. These are the F, K, P, and U codes (40 CFR 261.31-261.33) — F for waste from common industrial processes (e.g. spent solvents), K for waste from specific named industries, and P/U for discarded commercial chemical products (P for acutely hazardous, U for everything else).
- Characteristic waste — the waste isn't specifically named anywhere, but it exhibits one of four defined properties. These are the D codes, D001 through D043.
The four characteristics
- D001 — Ignitability (40 CFR 261.21): a liquid with a flash point below 60°C (140°F), a non-liquid that can spontaneously catch fire and burns vigorously, an ignitable compressed gas, or a DOT oxidizer.
- D002 — Corrosivity (40 CFR 261.22): an aqueous waste with pH ≤ 2 or ≥ 12.5, or a liquid that corrodes steel at a specified rate.
- D003 — Reactivity (40 CFR 261.23): normally unstable, reacts violently with water, generates toxic gas, capable of detonation, or several other specific triggers — reactive cyanide and sulfide wastes fall here too.
- D004-D043 — Toxicity (40 CFR 261.24): determined by the Toxicity Characteristic Leaching Procedure (TCLP, EPA Method 1311) — a lab test that simulates what could leach out of the waste in a landfill, checked against a specific concentration limit per constituent (metals like arsenic and lead, or organics like benzene and vinyl chloride).
ManifestMate's manifest form constrains the federal waste code field to RCRAInfo's own live code list, and the LDR notice tool cross-references a curated waste-code reference (name, CFR citation, and description) for whatever codes you enter — so you're picking from real codes, and seeing what they actually mean, not typing free text.
Why the determination happens once, at generation
A waste's codes are assigned based on its condition at the point it's generated — not after it's been diluted, mixed, or treated. That's a deliberate anti-dilution principle running through the whole hazardous waste program: you can't make a waste legally "less hazardous" just by mixing it with something clean. This is also why the codes on a manifest matter so much downstream — they're the receiving facility's starting point for figuring out what land disposal restrictions (covered next) actually apply.
Next: what happens after a waste has its codes — Land Disposal Restrictions.