(read: please spend more of your money on MY products!)
ALA is an essential fatty acid found in flaxseed, nuts, etc. It is used to successfully chelate small children and recover them from autism and is safe if Cutler protocol is strictly followed. Better yet it's super cheap and can be found in most drugstores.
You can injure yourself using "natural" chelators like cilantro and can poison yourself with table salt , so nothing can be termed completely safe - follow the established protocol that works!