USA, Canada / Obtaining a Polish passport being a US citizen [3]

I am interested in obtaining a Polish passport. I was told if I am 100% I can do that. Does anyone have information about this? A problem is starting to form because when my grandparents arrived at Ellis, it said they were German becasue Germany had owned Poland at the time. I am 100% on both sides. Does anyone know anythign about getting a passport being from the US. A friend told me all I have to be 50%. Thank you.