An experiment carried out in the 1970s might be to blame.
https://metro.co.uk/2023/08/29/we-might-have-already-found-alien-life-on-mars-and-drowned-it-19411445/?utm_source=dlvr.it&utm_medium=blogger
https://metro.co.uk/2023/08/29/we-might-have-already-found-alien-life-on-mars-and-drowned-it-19411445/?utm_source=dlvr.it&utm_medium=blogger