Charging sales tax on Printful items through Shopify - No tax state

[EldrThorn]

Hello! 

So, I've added a bunch of new products from Printful into my Shopify site. (I'm in the building process; it is not launched yet.) I'm looking through the product information and it shows that all of these products have a checked box to be charging tax. What exactly does this mean? I live in Oregon and there's no sales tax here. The checked box does not specify whether it's sales tax or not, and I wasn't given this option as I was filling out the product information. What am I missing? If it's sales tax, do I need to uncheck all of these products (and their many dozens of variants) by hand?

Any help would be super appreciated, thank you!