Substance and Toxicity databases

If you find some chemical in a test tube and you don't know what it is. Then here are a good list of places to check the effects and considerations online.

Toxic substances lists

Agency for Toxic Substances & Diseases Registry http://www.atsdr.cdc.gov/substances/index.asp

Toxic substances portal

Access the most important information about toxic substances and how they affect our health

http://www.atsdr.cdc.gov/toxguides/index.asp

ToxGuides http://www.atsdr.cdc.gov/toxguides/index.asp

Food Safety

Food Safety Hazard Guidebook