Underlying hazardous constituent
Underlying hazardous constituent means any constituent listed in 268.48, Table UTSUniversal Treatment Standards, except fluoride, selenium, sulfides, vanadium, and zinc, which can reasonably be expected to be present at the point of generation of the hazardous waste at a concentration above the constituent-specific UTS treatment standards.
Source
40 CFR § 268.2
Scoping language
When used in this part the following terms have the meanings given below: