Martian meteorite
Further findings of perchlorate and chlorate in the Martian meteorite EETA79001 and by the Mars "Curiosity" rover in 2012-2013 support the notion that perchlorates are globally distributed throughout the Martian surface. With concentrations approaching 0.5% and exceeding toxic levels on Martian soil, Martian perchlorates would present a serious challenge to human settlement, as well as microorganisms. On the other hand, the perchlorate would provide a convenient source of oxygen for the settlements.