Type a chemical from a label, receipt, cleaner, sunscreen, or food dye. I'll show you its EPA screening snapshot and whether it appears on four major reference lists.
The screening data comes from the EPA's ToxCast program, part of the Computational Toxicology and Exposure (CompTox) Dashboard. ToxCast runs chemicals through hundreds of laboratory assays to flag biological activity for research prioritization. We also check four major reference lists: California's Proposition 65 list, the WHO's IARC carcinogen classifications, the EU's ECHA Substances of Very High Concern list, and the TEDX endocrine disruptor list.
The EPA runs laboratory screening tests (called assays) on chemicals. Each assay tests whether a chemical produces a measurable biological response in a lab setting, such as interacting with a hormone receptor or affecting cell growth. "Active" means the chemical produced a statistically significant response in that particular assay. A higher number of active assays means the chemical interacted with more biological targets in screening, but this is in vitro (lab) data used for research prioritization. It does not directly tell you what happens in the human body at the levels found in everyday products. Dose, exposure route, and how your body processes the substance all matter.
The EPA CompTox Dashboard catalogs more than 1.3 million chemical records, but ToxCast screening has only been performed on a subset of them (roughly 10,000). If a chemical shows 0 assays, it means the EPA has not yet run high-throughput screening on it. This does not mean the chemical is safe. It means it has not been tested through this particular program.
No. The ToxCast percentage is not a safety rating. The EPA describes ToxCast as "in vitro screening data for prioritization and hazard characterization." It tells researchers which chemicals warrant further study, not whether a product is safe for consumers. The reference list matches (Prop 65, IARC, ECHA, TEDX) show where regulatory agencies have made formal determinations, but even those depend on dose and exposure context. This tool surfaces the data so you can see it for yourself.
Prop 65 is California's list of chemicals known to cause cancer or reproductive toxicity (~900 chemicals). IARC is the World Health Organization's cancer classification system (Group 1 = confirmed carcinogen, Group 2A = probable, Group 2B = possible). ECHA SVHC is the EU's list of Substances of Very High Concern under the REACH regulation. TEDX is the Endocrine Disruption Exchange list of chemicals with evidence of hormone-disrupting properties. A match means the chemical appears on that list. No match means it was not found, not that it has been evaluated and cleared.