The absorbent gel that is used in disposable diapers to absorb the urine is not toxic and will cause no harm to your babies or toddlers or child's skin.
The absorbent gel in diapers is Super Absorbent Polymer and is safe and also has wood pulp made from trees and recycled paper.
Another name for the gel in disposable diapers is sodium polyacrylate and it's non toxic but very absorbent to help draw the wetness away from your babies or child's skin.
You don't want to ingest the gel in diapers though because that could be harmful even though it's not toxic.
But getting the gel from diapers on the skin is not harmful and the gel just washes off.