are chlorine natural or humans made
Chlorine in Nature. Chlorine is a highly reactive element which practically does not exist by itself in nature, but only in combination with other elements. In some rare situations, such as in human tears, free chlorine as such can be detected. It is one of the most common elements in nature, where it is even more plentiful than carbon. Among the inorganic chlorinated substances, common salt is of course the best example.