Chemical compound
Sometimes people use the word 'chemical' just to talk about compounds that are dangerous. Many chemical compounds can be dangerous but are safe if they are used the right way. We all use chemicals every day and these chemicals have to be tested to make sure they are safe. Most dangerous chemicals are only used by scientists who have had special training in how to handle and use them. These chemicals might be poisonous, corrosive, explosive, they may catch fire easily, or they may react with other substances.