On the net, most of the research parrots a report published in May this year from the FDA (US) in Scientific American. The pros are outlined but basically, any good research on the down side is yet to be published even though the product has been around since 1979. I was concerned to see that the recommended maximum temperatures for use varied from 300 to 482 degrees Centigrade! Apparently this varies with each manufacturer and is marked on the packaging. But who keeps the paper wrappers for every item in their kitchen?