... causticity, soluble in water to generate orthophosphoric acid. Mass-produced polyphosphoric acid includes two specifications:1105%H3PO4(P2O576.0%)2115%H3PO4 ... , Danger Rule Code 93007 with Corrosive SignProduct Index: 115% Polyphosphoric Acid Index Item,IndexBest Quality,First QualityColority, Blackness ≤40 50Phosphoric ... .0100Heavy Metal (by Pb) Content, % ≤ 0.0030 0.0040 Polyphosphoric Acid (PPA)