Is Morton Pool Salt safe to kill fleas?

First let me start off by saying, we have no pets in our apartment but yet we have fleas, i don't understand it, but i have heard that sprinkling Morton Pool Salt into the carpet will kill the fleas, but is it safe for my two year old who puts everything in his mouth? I also heard spraying Lysol on the carpet will kill them but like i said my 2 year old sticks everything in his moth and i don't want anything that will harm him. How do i get rid of the fleas without harsh chemicals?