Biological hazard is something that can hurt living things, like when microbes or viruses make us sick. They can also hurt animals and plants too. They can be tiny, like a germ, or big, like a poisonous plant. They could come from food, water, air, or even people. It's important to take steps to stay safe, like washing your hands after you touch animals or their poop, or wearing a mask if you're around bad air.