The Martian surface may contain a toxic compound called magnesium perchlorate, which destroys bacteria under ultraviolet light, according to a new study  In the laboratory, the researchers exposed Bacillus subtilis to short-wave ultraviolet radiation in a condition similar to that on the Martian surface  They found that in this case, magnesium perchlorate is highly bactericidal, making Bacillus subtilis lose its viability in just a few minutes
The bactericidal activity of iron oxide and hydrogen peroxide on the Martian surface combined with magnesium perchlorate is enhanced tenfold
 The researchers believe that this shows that Mars is not suitable for life