For which of the following fumigants is a warning agent specifically required?

A warning agent is required for both methyl bromide and chloropicrin due to their highly toxic nature and the potential risk they pose to human health and the environment. The inclusion of a warning agent serves as an important safety measure that helps to alert individuals in the vicinity of the fumigation site when these substances are present.

Methyl bromide is known for its acute toxicity and harmful effects on the central nervous system, which is why the presence of a warning agent can provide an immediate indication of its presence in the air. Chloropicrin, on the other hand, is used as a warning agent itself and is responsible for its pungent odor, which serves to notify people of its potential hazards as it is also highly toxic and can cause severe respiratory issues.

In contrast, other fumigants like MITC may not have the same requirements for a warning agent due to their different toxicity profiles or usage scenarios, which do not present the same level of immediate danger to humans when compared to methyl bromide and chloropicrin. Thus, the identification of both methyl bromide and chloropicrin as needing a warning agent is crucial for minimizing the risks associated with their use in fumigation processes.