The determination of the precise chemical form or oxidation state of a substance in waste, critical for accurate hazard assessment. Different chemical species of the same element can have vastly different hazardous properties and threshold concentrations. For example, chromium(III) and chromium(VI) have different toxicities; speciation is particularly important for HP14 ecotoxicity assessment of metals like zinc, copper, and chromium. Required under WM3 guidance when chemical form affects classification.