Selenium is found in a few rare minerals such as crooksite and clausthalite. In years past it has been obtained from flue dusts remaining from processing copper sulfide ores, but the anode metal from electrolytic copper refineries now provide the source of most of the world's selenium. Humans and animals can use both inorganic and organic selenium compounds. In the body, selenium helps prevent damage by oxygen to tissues. However, it is harmful to humans and animals when eaten in amounts that are not much higher than the amounts needed for good nutrition. Selenium IDE is an integrated development environment for Selenium tests. It is implemented as a Firefox extension, and allows you to record, edit, and debug tests.