The first consumer grade nickel–metal hydride batteries (NiMH) for smaller applications appeared on the market in 1989 as a variation of the 1970s nickel–hydrogen battery. NiMH batteries tend to have longer lifespans than NiCd batteries (and their lifespans continue to increase as manufacturers experiment with new alloys) and, since cadmium is toxic, NiMH batteries are less damaging to the environment.