I've heard of others using parchment for transferring pizza and bread to the stone but have never done it myself. It was always my understanding that parchment paper was designed to be used at temperatures under 420F. I did some research on health effects and could only find limited information. According to some internet sources, parchment manufacturers use either a quilon (Teflon?) or silicone coating. Both are approved by the FDA however at higher temperatures some say that quilon can become toxic. I'd recommend looking into what is being used on your paper. From what I've read silicone seems to be OK at the higher temperatures although not necessarily designed for the higher range. In todays day and age I'd be weary of using any product outside of the parameters it was designed to be used. There's no sense in exposing yourself to more chemicals than you are already exposed in your day to day life.
You can pick up a decent wooden pizza peel for $20 or less. Get that and some semolina, problem solved.