The public, however, considers just the opposite to be true. Overview of Synthetic Insecticides As a group, the synthetic compounds include both very hazardous and very safe chemicals. On the other hand, the safe compounds often have little or no toxicity to mammals. Some are extremely selective, and some pose no residue problems at all. The properties of the naturally occurring chemicals that help protect plants vary greatly.
Some chemicals are quite hazardous, while others are very safe.
Their toxicities can be acute or chronic, and some even cause concerns over residues. Risks from natural versus synthetic insecticides.