Borax is not toxic but for some reason, many websites incorrectly say it is. I suppose in high doses everything is toxic. I think the confusion comes with boric acid which is toxic even at small doses.

In sum, borax is wholly natural and has no inherently toxic ingredients. It doesn't cause cancer, accumulate in the body or in nature, or absorb through the skin. Because the dose makes the poison, borax is not harmful to the body or the environment with normal, external usage any more than salt or baking soda is.