It most certainly can kill you. First hit when searching if natural gas can kill you

i work with people (in a hospital that technically requires "natural" colors) that have purple, green, pink, blue, etc. colored hair. And any combination of them. Interesting dye colors are just the way these days.

You could always just shave it off. :-p

i'm keeping my hair red by dying the gray roots and i think by now it has to be almost all gray underneath. Seriously been considering just chopping it off and letting that grow out. But my hair grows so slowly i'd be stuck with short hair for years. Meh.