I've had mine since Dec. 2007. And,sure enough it appeared my recent (last month) mammogram... just as I was told that it would. To my knowledge, these clips are entirely safe. I personally, have no complaints with it. In fact, it gives me a measure of comfort knowing that it's there for future referencing. When I consider the purpose that it serves, I couldn't imagine having mine removed.
sorry for the double post question, I didnt think my other question posted due to an error.