Have hair relaxers been approved by the FDA?

i'm speaking of lye and ';no lye'; relaxers.Have hair relaxers been approved by the FDA?
i heard they are but i think it's a conspirarcy ( lol ) . they prolly paid off the fda w|o them checkinq . like c'mon ! they can BURN your scalp %26amp;nd hair how is that safe ? relaxer free for 10 months :-D .