Acronym for 'unknown variable composition or biological substance'.
Means any of the following:
(a) a chemical of unknown or variable composition;
(b) a complex product of a chemical reaction;
(c) biological material, other than a whole animal or a whole plant.
Unknown or Variable Composition, Complex Reaction products and Biological Materials (UVCBs) have some uncertainty in their chemical identity. They don’t have definite molecular formulas or chemical structure diagrams. They often have variable structural elements that are undefined or have unknown structural elements.
Some substances can only be represented by partial or incomplete chemical structures. In other instances the composition can only be described in terms of a complex combination of several different known or unknown components.
The method of manufacture can also identify a substance. For a substance manufactured by a chemical reaction, identification can be stated in terms of the:
- immediate precursor substances and other reactants that participate in the final reaction sequence used to manufacture the substance
- the nature of the reaction (e.g., ethoxylation or bromination)
For a substance derived from a source without chemical reaction, processing information identifies the source and method of derivation (e.g. distillation).
Providing a 'proper name' for a UVCB
If you need to give us the name of your UVCB and a CAS name is not available, you should describe the chemical composition or starting materials or sources as completely as possible.