You may find this article useful:
http://www.learningabouteos.com/index.php/2014/02/07/essential-oils-and-children/
In the article is a list of oil that are safe for children. There is also a link to find out which oils should be avoided.
Hope this helps!
In short, essential oil needs to be properly diluted (http://www.learningabouteos.com/index.php/2013/08/07/properly-diluting-essential-oils/) to be used on babies and toddlers.
Anonymous