I love how the worrymongers come out as soon as the word toner crops up. You handle printed material every single day that will normally be printed using solvent based inks yet you worry about handling toner. 5 minutes in your average city centre at rush hour will more than lilley do you more harm.
It's only £12-14 for a refill kit with the chip reset tool, you don't have to cut/melt the cartridge on the 4200. A pre refilled cart is £20-25 delivered, it's hardly expensive to run... and those prices are incluiding delivery, for the sake of £8-11 it's not the hardest of jobs to do but if you are worried just get a pre refilled cart.