Pesticides are designed to kill. That fact often gets softened by marketing language—“crop protection,” “pest control,” “plant health.” But at their core, many pesticides work by attacking nervous systems, shutting down respiration, disrupting cell function, or poisoning organs. Insects die because of these effects. Humans die for the same reasons, just less predictably and often more slowly.

You often hear warnings about toxic chemicals and how dangerous they can be, but the meaning of the term is usually left vague. A toxic chemical is not a rare or exotic substance found only in laboratories or industrial accidents. According to the definition used by the U.S. Environmental Protection Agency, a toxic chemical is any substance that can harm human health or the environment if it is inhaled, swallowed, or absorbed through the skin. This definition is intentionally broad because harmful exposure is not limited to unusual materials.