Data sources
SDS Lookup builds its chemical pages from public data: mainly PubChem and the safety databases it aggregates, plus the UN GHS Revision 10 text for hazard and precautionary statements. We show the source for each chemical-specific fact. This page lists the sources and explains how we handle classifications that disagree.
Sources
| Source | What we use it for |
|---|---|
| PubChem | Open chemistry database run by the US National Library of Medicine (NCBI). The backbone of our chemical pages: identifiers, names, properties and the aggregated safety and hazard annotations from its data contributors. |
| ECHA C&L Inventory | Classification and labelling notifications from companies to the European Chemicals Agency. We use the aggregate: how many companies reported each classification. |
| EU CLP Annex VI (harmonised classifications) | Legally binding EU classifications for selected substances. |
| NIOSH Pocket Guide to Chemical Hazards | US National Institute for Occupational Safety and Health: exposure limits (REL, IDLH), PPE, first aid and physical data for common workplace chemicals. |
| OSHA | US Occupational Safety and Health Administration: permissible exposure limits (PELs), the Hazard Communication Standard and chemical information. |
| NOAA CAMEO Chemicals | Response information database: reactivity, hazards, emergency response and incompatibility information. |
| HSDB (Hazardous Substances Data Bank) | Toxicology, environmental fate and safety data peer-reviewed by the National Library of Medicine, accessed through PubChem. |
| ILO International Chemical Safety Cards (ICSC) | Standardised summaries of essential health and safety information on chemicals, produced by the International Labour Organization and WHO partners. |
| Haz-Map | Occupational exposure database linking chemicals to jobs and health effects. |
| UN GHS Revision 10 | The wording of hazard (H) and precautionary (P) statements, pictograms and classification criteria, from the UN Globally Harmonized System, Revision 10. |
Most chemical data on this site is retrieved through PubChem, which collects annotations from the sources above and many others. Where a page quotes one of those contributors, the source is named next to the value. We link to these sites for convenience; they are independent of us, and the original publisher's version is the authoritative one.
Hazard and precautionary statement text
The wording of hazard statements (H-codes) and precautionary statements (P-codes) comes from the UN GHS Revision 10 data, not from retyping. You can browse them in the hazard statement reference and precautionary statement reference. National systems adopt different parts and revisions of the GHS, so the text a supplier uses on a label in your country may differ slightly. See the UN GHS overview.
Why classifications can differ
Two sources can give different GHS classifications for the same chemical name, and both can be legitimate:
- Different test data and judgment. Each supplier classifies using the data it has. Companies are expected to classify according to the criteria, but may weigh studies differently.
- Purity, impurities and form. A solution, a powder and a technical-grade product are not the same, and neither is a chemical at different concentrations.
- Different GHS building blocks and revisions. The US (OSHA HazCom), the EU (CLP), Canada (WHMIS) and others have not adopted exactly the same categories. See OSHA HazCom and EU CLP.
- Notification versus harmonisation. In the EU some substances have a binding harmonised classification; for the remaining hazard classes and for most other substances, companies classify themselves, and the notifications they send to ECHA can vary.
- Age of the information. Classifications and the data behind them change over time.
How we choose the primary classification
- EU harmonised classification first. If the substance has a harmonised classification (CLP Annex VI), we show it as the primary classification and say so, because it is the only classification with a binding legal status in the EU.
- Otherwise, the ECHA aggregate with the most reports. If there is no harmonised classification, we show the classification that the largest number of notifying companies reported to the ECHA C&L Inventory, along with the number of reports. A larger number of reports is a sign of consensus, not proof of correctness.
- No classification found. If neither is available, the page says so rather than guessing.
The primary classification is a convenience for orientation. It is not the classification on your product's label. Where percentages are shown, they are the shares of notifications reporting a given hazard statement. Always use the classification in the SDS supplied with your product.
Frequently asked questions
Where does SDS Lookup get its chemical data?
Mainly from PubChem and the databases it aggregates, including the ECHA C&L Inventory, EU CLP Annex VI harmonised classifications, the NIOSH Pocket Guide, OSHA, NOAA CAMEO Chemicals, HSDB, ILO ICSC and Haz-Map. Hazard and precautionary statement wording comes from UN GHS Revision 10.
Why can the same chemical have different GHS classifications?
Suppliers classify using their own data, purity, impurities and concentration, and countries adopt different parts and revisions of the GHS. Classifications reported to ECHA by many companies often disagree. A harmonised classification in the EU is the one legally binding exception.
Which classification does SDS Lookup show first?
The EU harmonised classification (CLP Annex VI) when one exists. Otherwise the ECHA C&L Inventory classification that was reported most often by notifying companies, with the number of reports shown.
Can I use this data in place of a supplier SDS?
No. The supplier's SDS describes the exact product you have. Our pages are reference summaries.