Simplify the following text for a Grade 10 native English-speaking person.
Original: Legally and in hazardous chemical labeling , poisons are especially toxic substances ; less toxic substances are labeled `` harmful '' , `` irritant '' , or not labeled at all .
Simplified: Legally and in hazardous chemical labeling , poisons are especially toxic substances . Less toxic substances are labeled `` harmful '' , `` irritant '' , or not labeled at all .