it's a federal law to have a MSDS sheet for pure and chemical household products and if you request one you will get it. Here is a website that has a list of most starches.
http://householdproducts.nlm.nih.gov/index.htm
I think Mary Ellen's has tapioca in it. I don't like it at all. I like Faultless and Niagara in the pump bottle.