Pesticides are chemicals that are used to keep insects and other creatures from eating crops and vegetation. Pesticides don’t only kill animals that eat the crops, but they kill many other types of insects that are harmless to crops but happen to live where the pesticides are sprayed. Rain and water that fall on the plants can wash the pesticides into rivers, streams and lakes nearby, which can cause the death of many more animals. Some pesticides that have been used in the past have been found to be harmful to humans and can’t be used anymore. These chemicals can be stored in the bodies of humans and animals and cause illness even many years later. Even though some pesticides are illegal to use, there are still many more in use that can be harmful to humans and the environment.