Apparently the meteorite hit a rather sandy rock formation or soil horizon, so it would have really pulverized a lot of the sand into fine dust ithat would linger in the air inside the crater.  Inhaling quartz dust will really irritate your throat and lungs.  Plus, the heat of impact would have fused a lot of material from the soil, and from the disintegrating meteorite, into fine particles.  Perhaps some of those could be suspended in the air, too.  I don't know what inhaling colloidal-sized glass shards does for you, but I doubt that it does you much good.

In a worst-case scenario, I suppose long-term exposure could cause that occupational disease of miners and sandblasters that's the longest word in the English language.