All of them. Maybe.
No one knows long-term health risks of most of the chemicals in our environment, including those we intentionally put on our scalps.
That being said, hair color dyes have been around for decades, and used by women for their entire lives. Right up until they die of something that (probably) is totally unrelated to hair dye chemicals. So, weigh the (low) risk/benefit (?) and decide if it's worth it!