The results of PFAS selection with the combined use of fingerprints and subsequent ABAS selection correspond exactly to the results when using ABAS on all input molecules -with one exception of CDK for Definition A where the direct ABAS search finds one structure in addition to the fingerprint+ABAS process, which is OCID190080191030 (PubChem CID 117959248) with a very extensive polycyclic aromatic structure, shown in Figure . Finalized PFAS CORE and Patent Lists via OCL Since compound structures may be described by syntactically correct SMILES strings but these may represent non-existing compounds, for example if they contain hypervalent atoms or non-existing isotopes (as discussed above), a final cleaning step was implemented based on the results above. Both input sets from CORE and patents from above were used, along with the following procedure to derive a dataset of both valid normalized and standardized SMILES of PFAS classified molecules according to the three definitions using the OCL toolkit: