U239 RCRA waste code Ignitable, toxic paint & ink thinner, thrown away unused.

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Based on 40 CFR 261.33 and EPA guidance
Nothing is stored

U-listed waste
Xylene

U-list unused product.

Solvent drum with vapour, drawn for RCRA waste code U239, xylene. Ignitable, toxic paint & ink thinner, thrown away unused. — Ignitable & toxic U-listed hazardous waste for unused xylene, a solvent in paints, inks & thinners.

Is U239 hazardous waste?

Yes, when the listing applies. U239 is the U-listed code for unused xylene thrown away, including off-specification product and qualifying residues. It is nonacute, not a P-listed acute waste. It depends on the product and how it is discarded, not on a TCLP result.

The listing is printed as “Benzene, dimethyl- (I)” and “Xylene (I)”, but also as “Benzene, dimethyl- (I,T)”. These disagree on whether the hazard is ignitability alone or ignitability and toxicity. Whether U239 still applies once the waste is no longer ignitable is unsettled under 261.3(g).

On a required hazardous waste manifest, put U239 in Item 13. Read the VSQG exemptions and empty-container rules and pharmaceutical containers too.

What does U239 cover?

This is xylene that was never used, such as a commercial chemical product, an off-specification batch, a residue in a non-empty container or a spill cleanup residue. It must be pure, technical grade or the only active ingredient of the product. Xylene that has already worked as a solvent needs the spent-solvent assessment instead.

CAS: 1330-20-7
Table entries: Benzene, dimethyl- (I) / Xylene (I) / Benzene, dimethyl- (I,T)
Printed hazard annotations: “Benzene, dimethyl- (I)”: (I); “Xylene (I)”: (I); “Benzene, dimethyl- (I,T)”: (I,T).
Rule: 40 CFR 261.33(f)

Is xylene waste always U239?

Code	When it fits
U239	The unused chemical is thrown away pure, in technical grade or as the only active ingredient. Qualifying product residues are included.
F003	It has been used as a solvent, alone or blended before use only with F003 solvents. Still bottoms from recovery are included.
F001–F005	Before use, the blend held an F003 solvent plus at least 10% by volume of F001, F002, F004 or F005 solvents in total.
Characteristic waste (D001–D043)	A used chemical or a different formulation has a hazardous characteristic. Assess any process listings too.

Both rows can apply to one waste, because a listed unused product can also have a characteristic. The chemical merely turning up in a manufacturing waste doesn't make the waste U239. Match the waste’s origin, formulation and use history. Mixing or treating listed waste doesn't generally remove the listing. That takes an exclusion, an exception or an approved delisting. Using the chemical as an ingredient or reactant doesn't by itself make it a spent F-listed solvent. Read each listing’s before-use blend conditions.

Which wastes take U239?

Waste	When it’s U239
Paint thinner	Unused thinner thrown away as a commercial chemical product with xylene as its only active ingredient.
Solvent-contaminated wipes	The wipes hold unused xylene that meets U239.
Unused xylene	The discarded commercial product is pure or technical-grade xylene, or xylene is its only active ingredient.

Which codes sit beside U239?

Code	What it is
U235	Tris(2,3-dibromopropyl) phosphate
U236	Trypan blue
U237	Uracil mustard — a cancer-treatment compound
U238	Ethyl carbamate (urethane)
U240	2,4-D, salts and esters — a herbicide
U243	Hexachloropropene
U244	Thiram — a dithiocarbamate fungicide
U246	Cyanogen bromide (CN)Br