Source order
- Federal, state, county, and local government
- Certified laboratory directories
- Universities and peer-reviewed research
- Standards bodies
- Manufacturer documents for product facts
- Clearly labeled secondary evidence
Evidence labels
Documented: directly cited. Possible: needs testing. Editorial judgment: synthesis using stated criteria. Unknown: not verified.
Dates and limits
Time-sensitive pages show review dates. Sources can change, and articles cannot replace individual testing.
Last reviewed: September 7, 2026.