I'm not a Mars colonisation advocate, but sounds like exposure to that may be manageable:

"Perchlorate is toxic to people only in the sense that it can disrupt the production of thyroid hormone, an important growth hormone needed by babies in the womb for normal development." (from https://www.scientificamerican.com/article/perchlorate-life-...)

Lots of people have this condition without perchlorate after all and it's just simple meds to fix it.