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5.3 The Mixture Rule

If you have a characteristic hazardous waste and it is inadvertently mixed with a nonhazardous waste, the mixture will be considered hazardous waste only if it retains the hazardous characteristic.

If you have a nonhazardous waste, e.g. used oil, and you contaminate it with a listed hazardous waste, e.g. F005 spent solvent; the entire waste will be classified as F005 listed hazardous waste.

A few wastes are listed only because they are ignitable or reactive. In these cases, if the resulting mixture is no longer ignitable or reactive, then the mixture is not considered a listed waste.

Examples: Spent solvents (F003), such as methanol or acetone, are listed hazardous wastes and are ignitable. If these solvents are unintentionally mixed with a non-ignitable nonhazardous waste, the mixture will still be considered hazardous, unless the mixture is not ignitable.
Please note that intentional dilution of a hazardous waste is not allowed without a permit