NASA Needs to Know More About Mars’ Potential Dangers

If humans are to walk across Mars safely, far more data is needed about the hazardous environments of the red planet, aerospace engineers and analysts told a presidential commission Thursday.
For one, toxic materials may exist in the soil. Airborne dust, too, may plague the day-to-day tasks undertaken by an expeditionary crew. Furthermore, little is known about the degree of radiation cascading through the thin martian atmosphere.