A number of cheminformatics tools have been developed in recent years in the Computational Chemistry & Cheminformatics Branch (CCCB) of the Center for Computational Toxicology and Exposure. The DSSTox chemistry database underpins all cheminformatics tools and provides the foundation for multiple Dashboards including the CompTox Chemicals Dashboard (https://comptox.epa.gov/dashboard) and the proof-of-concept Cheminformatics Tools (https://www.epa.gov/chemical-research/cheminformatics). These applications provide access to property, hazard, exposure and safety data. This presentation will give an overview of available tools and how they may serve research applications regarding fluorine-free foams.

1. Cheminformatics Tools to Access Data
for PFAS and Constituents of
Fluorine-Free Foams
Antony Williams
Center for Computational Toxicology & Exposure, U.S. Environmental Protection Agency
http://www.orcid.org/0000-0002-2668-4821
November 2023: Sandia National Labs PFAS Workshop
The views expressed in this presentation are those of the author and do not necessarily reflect the views or policies of the U.S. EPA

2. CCTE Cheminformatics Tools
• DSSTox – the chemistry database under all
cheminformatics tools
• https://doi.org/10.1016/j.comtox.2019.10009
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3. CompTox Chemicals Dashboard
https://comptox.epa.gov/dashboard
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• Searching 1.2M chemicals – CAS Numbers,
systematic names and synonyms, structures

4. CompTox Chemicals Dashboard
• A publicly accessible website delivering access to:
– ~1.2M chemicals with related property data
– Experimental and predicted physicochemical property data
– Experimental Human and Ecological hazard data
– Integration to “biological assay data” for 1000s of chemicals
– Information regarding chemicals in consumer products
– Links to other agency websites and public data resources
– “Literature” search capability for chemicals using public resources
– “Batch searching” for tens to thousands of chemicals
– Over 15,000 of the chemicals are classed as PFAS Chemicals
(but be cautious regarding the definition of a PFAS”…)
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5. To understand FFF it helps to
understand PFAS also
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6. 1 of ~1.2M Chemical Pages
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7. Physicochemical Properties
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8. Experimental Data
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9. What is PFOS Called?
Synonyms, CASRNs and more
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10. Substance Relationship Mappings
• Similar compounds - based on structure
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11. Are there Similar Compounds?
127 chemicals >0.8 match factor
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12. Substance Relationship Mappings
• Similar compounds - based on structure
• Structure mappings - between parent and
salts, multicomponent chemicals, isotopomers
– Useful for creating structure-based category mappings
• Related substances – monomer to polymer,
parent to transformation products
– Ideal way to create a chemical description of a formulation
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13. Relationships in the data
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14. Chemicals in an AFFF foam
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15. Chemicals in an AFFF foam
• We extract data from many sources
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16. How to compare Hazard Data?
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• Search thousands of chemicals based on
CASRN, names and identifiers
• Harvest available data including properties,
toxicity data, chemical relationships, category
mappings, presence in lists

17. How to compare Hazard Data?
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18. How to compare Hazard Data?
NOT Easy to interpret…
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19. Profiling the toxicity of chemicals
MUCH easier…
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• The Hazard Comparison module profiles
toxicity across chemicals
• https://www.epa.gov/chemical-research/cheminformatics

20. Obtain Data and Profile Any Chemicals
• If we have the chemicals in DSSTox data can
be retrieved and the chemical profiled
• Imagine any FFF mixture where constituents
are known – harvest data and profile hazard
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21. Safety Profiling
(Work in Progress)
• New module in development (NOT public)
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22. Analytical Methods and Open Spectra
(Work in Progress)
• ~4000 methods extracted
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23. Analytical Methods and Open Spectra
(Work in Progress)
• ~4000 methods extracted (100 PFAS methods)
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24. Conclusions
• CompTox Chemicals Dashboard supports
research at EPA in numerous ways
– Assembly, integration and curation of chemistry data
– Relationships in the data enrich navigation between
chemicals
– Flexible searches – names, structures, formulae, masses
• Proof-of-Concept tools online/in development
– Hazard and Safety Profiling
– Structure/substructure/similarity search
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25. Papers of Interest
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26. Papers of Interest
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27. Papers of Interest
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28. Contact
Interested in a demo and overview of our tools?
Contact me:
Antony Williams
NCCT, US EPA Office of Research and Development,
Williams.Antony@epa.gov
ORCID: https://orcid.org/0000-0002-2668-4821
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