Why is cobalt poisonous?

Cobalt is poisonous because it is radioactive! flowers, plants, trees..etc are safe from it, but humans and animals can die from it! I have not done a whole lot of research on it, so you should look into it we dont want factories to produce things out of it. OH NO! they already have! cobalt is in porcelains, tiles and enamels, it makes proplusion enginges, it treats cancer with its radioative powers it kills the bad cells, it even makes artificial joints!