This presentation was delivered at the 2019 Product Stewardship conference in Columbus, OH on September 11th. The description of the session is below "Mention the phrase "chemical nomenclature" and you'll likely receive more than a few head scratches and eye rolls. The fact remains, however, that these important rules, implemented by EPA under the Toxic Substances Control Act (TSCA), influence many of the products you buy every day. The existing system could benefit from improved rules and guidance. Here are some current issues: Manufacturers can be locked into specific suppliers due to naming conventions; existing chemicals may require pre-manufacturing notices if sourced from a different organism; and outdated, sometimes incorrect names on inventory cannot be corrected by anyone other than the original notifier, a particularly difficult situation if the manufacturer is no longer in business. These issues can proliferate as more and more countries inherit nomenclature problems that started here, or develop nomenclature systems of their own. Come and learn about existing problems, international approaches, and potential solutions to one of the fascinating, yet arcane aspects of the TSCA framework."

1. EPA CompTox Chemicals
Dashboard
A chemical integration hub
Antony Williams
US-EPA National Center for Computational Toxicology
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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. The CompTox Chemicals Dashboard
https://comptox.epa.gov/dashboard
• Integration hub for >875,000 chemical
substances
• Managing the complex nature of substances and
identifiers – synonyms, CAS Registry Numbers
• Each substance has a unique ID mapped to
structure (when available), CASRN(s), multiple
synonyms
• Aggregated sets of chemical lists of interest
• UVCB substances - unknown or variable
composition, complex reaction products or
biological materials – includes mappings to 2

3. CASRN or Name Search for 875,000
chemicals
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Type-ahead search for millions of
identifiers including systematic
nomenclature, synonyms and CAS
Registry Numbers

4. Example Record - Ergocalciferol
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5. Ergocalciferol – Identifiers include names and
CAS
Total of 112 identifiers for this chemical
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6. Systematic Names are complex and rules-
based
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7. Synonyms are simply by declaration
• D-Tracetten
• Ercalciol
• Ergorone
• Fortodyl
• Geltabs
• Hi-Deratol
• Metadee
• Mulsiferol
• Mykostin
• NSC 62792
• Oleovitamin D
• Oleovitamin D2
• Ostelin
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• Radiostol
• Radsterin
• Rodine C
• Shock-ferol
• Sterogyl
• Uvesterol D
• Viosterol
• Vitavel-D
• Activated ergosterol
• Calciferolum
• EINECS 200-014-9
• Hyperkil
• Rules-based systematic
names can be converted to
structures (in general)
• Synonyms, and many UVCB
identifiers are vague and
ambiguous and commonly
used for “look-up” only

8. Converting Systematic Names to Structures
e.g. https://opsin.ch.cam.ac.uk/
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9. A chemical can have many CAS Registry
Numbers
• There are various flavors of CAS Registry
Numbers
• Active
• Alternate
• Deleted
• Some chemical substances have hundreds of
deleted CAS numbers!
• There are ways to map distinct structures but
this is difficult for mixtures and ambiguous
chemicals
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10. Dealing with Complex Substances – e.g.
PCBs
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11. PCBs – members of the category
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12. How does the dashboard deal with UVCBs?
• n-Nonylphenol – indicated as a mixture of various sustituted forms
using “Markush structure” representation
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13. How does the dashboard deal with UVCBs?
• n-Nonylphenol – indicates a mixture of
substituted forms using “Markush structure”
representation
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14. But there are various nonylphenols…
• 25154-52-3 General class
• 104-40-5 4-n-Nonyl phenol
• 84852-15-3 Branched 4-Nonyl phenols
• 11066-49-2 Isononylphenols
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15. Branched form is of interest as endocrine
disruptor
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Estradiol Branched
nonylphenol

16. Dodecene – is a family..
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17. “Propylene Tetramer” substring search
• STRING Search gives two
substances
• A search for “propylene tetramer”
substring gives 7 substances
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18. Dashboard Segregated Lists
• Lists of chemicals to serve specific
interests in chemical substance
sets
• TSCA Inventory, active, non-
confidential
• Pesticides
• Lists assembled to serve projects
and communities as needed
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19. Conclusions
• Dashboard is a collection of
substances and data. ~875,000 and
growing
• Data is under constant curation
• Mapped relationships between
chemicals is of value for complex
substances
• Support for UVCB chemicals is built-in
• Chemistry is complex and informatics
solutions are more complete for
distinct structures than complex
substances 19
Data Quality
Flags
The category Polycyclic Aromatic Hydrocarbons