What type of reproductive toxin can harm a fetus during early development?

A teratogen is a type of reproductive toxin that can cause malformation or harm to a developing fetus during critical stages of development, particularly in the early gestational period. Exposure to teratogens can lead to a variety of adverse outcomes, including birth defects, developmental delays, and other health issues in newborns. This is significant in the context of hazardous waste operations, where exposure to hazardous materials can pose risks not only to the worker but also to their potential offspring.

Mutagens, which are agents that cause changes to the DNA, can lead to genetic mutations but do not specifically target the developmental process of the fetus. Sterilants are chemicals used to inhibit the reproduction of organisms, but their role is more about preventing reproduction in adults rather than affecting fetal development. Nephrotoxins are substances that primarily affect the kidneys, and while they can have significant health implications, they do not specifically relate to fetal harm or development. Thus, the defined impact of teratogens on fetal health during early development makes them the correct choice for this question.