Animals in southern Iceland are at risk of fluoride poisoning if they inhale or ingest the ash from the recent volcanic eruption. Fluoride poisoning can lead to internal bleeding, long-term bone damage and tooth loss.
According to BBC News:
“The fluoride in the ash creates acid in the animals' stomachs, corroding the intestines and causing hemorrhages. It also binds with calcium in the bloodstream and after heavy exposure over a period of days makes bones frail, even causing teeth to crumble.”