Last month was the hottest May on record—and with heat comes death for many of the world’s more fragile organisms. We've seen reports that coral bleaching has reached alarming levels this year, threatening the world’s greatest reefs. Even the Great Barrier Reef off the coast of Australia is not immune. Now, it appears that there’s yet another human-induced risk: Scientists have also found that a common ingredient in sunscreen is killing and mutating corals in tourist spots. The new evidence of harm to corals comes as the most the most widespread coral bleaching event in recorded history is sweeping the world’s oceans.