Spending time on the moon just got a little more complicated. A new study has found that lunar soil is extremely toxic and that even small amounts of lunar dirt could be damaging to lungs, reports Popular Mechanics. Astronauts on the Apollo missions first noticed problems with space dust when it clung to their spacesuits and was difficult to brush off after moonwalks. They also suffered watery eyes, sore throats, and sneezing—a condition that Apollo 17 astronaut Harrison Schmitt described as "lunar hay fever," per the Smithsonian. Their reaction was consistent with a large body of research that shows breathing dust from coal mines and volcano eruptions can cause long-term lung damage and increase risk of cancer.
To test the risk of moon dust, researchers at Stony Brook University School of Medicine in New York grew a batch of human lung cells and mouse brain cells, then exposed the cells to various types of earth dust that closely resemble lunar dust. They found that exposure to moon-like particles killed up to 90% of all the cells and virtually destroyed DNA. One reason lunar dirt is so toxic is that unlike earth soil, it is constantly exposed to "charged particles from the upper layers of the sun," per Popular Mechanics. The study didn't use real lunar dust, Gizmodo notes, but moon visitors still have reason to worry: "If there are trips back to the moon that involve stays of weeks, months, or even longer it probably won’t be possible to eliminate that risk completely," lead study author Bruce Demple says in a statement. (Meanwhile, Russia and the US are building a moon base.)