Data sources & attribution
Each record preserves its source identity. Source-curated facts, derived browsing groups and PubCAS calculations are distinguished throughout the site.
EMBL-EBI ChEBI
Identity, CAS cross-references, names, formulas, mass, structure and ontology. Release 255, published 9 September 2026. The first release selects 1,000 three-star source entries.
NIH / NCBI PubChem
Additional molecular properties and official compound links, connected using exact InChIKey matches. PubChem computed descriptors remain labelled separately.
CDC / NIOSH
Official occupational chemical safety references. CAS-to-page links come from the NIOSH Pocket Guide CAS index. Original guide content remains on the official website.
NITE / Japanese government
Government GHS classification records and selected source-reported endpoints. The source year, identifier and original classification are retained.
CAS Substance Classes
Reference for the names of the 19 CAS substance classes. PubCAS applies its own browsing groups using ChEBI information; official CAS record assignments are not imported.
NCBI PubMed
Selected publication metadata for cross-references listed in ChEBI. Article association does not establish a particular experimental finding or clinical use.
External lookup services
ECHA, EPA CompTox, NIST, CAS Common Chemistry, Wikipedia and national authorities are linked as record, lookup or search destinations. A link does not imply that the linked database has a record for every substance or endorses PubCAS. Restrictions on downstream data reuse remain with the original provider.
Reuse PubCAS exports
ChEBI-derived data retain the CC BY 4.0 attribution requirement. Cite EMBL-EBI ChEBI and the source entry. Keep any separately attributed source data and their conditions. Calculations and formatting do not remove underlying source conditions.