California waste code 451 Residue left by cleaning parts in a degreaser.

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Based on California Title 22 and DTSC guidance
Nothing is stored

Sludges
Sludge from degreasing

A degreasing operation produced the hazardous sludge.

Hazardous sludge from a degreasing operation. Liquid solvent from the same operation is coded by its solvent type.

Is California code 451 hazardous waste?

Not from the code alone. Waste must first be found hazardous. Code 451 isn't a restricted code, but a restricted category that fits takes priority over it. A code that isn't restricted doesn't make waste non-hazardous.

When a shipment needs the Uniform Hazardous Waste Manifest, enter 451 in Item 13 for the waste line. Use one California code, plus the federal RCRA codes when the waste is federally hazardous.

RCRA waste meets a federal listing or characteristic, with no federal exclusion that applies. Non-RCRA waste is hazardous under California rules only. California presumes hazardous waste is RCRA unless the generator shows it isn't, so keep that determination.

What does California code 451 cover?

This code is for hazardous settled residue left when grease or oil is removed in a degreasing operation. It doesn't cover the separate liquid solvent stream.

Official wording: 22 CCR division 4.5, chapter 11, Appendix XII(b)

Is degreasing waste California code 451, 211 or 214?

Code	When it fits
451	The hazardous settled residue came from removing grease or oil.
211	The waste is spent halogenated liquid solvent and restricted code 741 does not apply.
214	The waste is a spent solvent mixture and no specific or restricted solvent entry fits.

Separate the sludge from the liquid solvent before choosing a code. Restricted code 741 takes priority when total HOCs in the liquid reach 1,000 mg/L.

Which wastes take California code 451?

Waste	When it’s 451
Degreasing sludge	The settled residue came from removal of grease or oil

Which codes sit beside California code 451?

Code	What it is
411	Alum or gypsum sludge
421	Lime sludge
431	Phosphate sludge
441	Sulfur sludge
461	Paint sludge
471	Paper-processing sludge or pulp
481	Tetraethyl-lead sludge
491	Other hazardous sludge