Which of the following substances is commonly used as a fumigant?

Methyl bromide is commonly used as a fumigant due to its effectiveness in controlling a wide range of pests, including insects and weeds. Its application extends across various settings, particularly in agriculture for soil fumigation and for the treatment of commodities and structures. Its ability to penetrate materials allows for thorough pest control within the environment being treated.

The use of methyl bromide is particularly important because it has been shown to be a potent solution for serious pest infestations, and due to its volatileness, it is capable of dispersing effectively in the space being fumigated. This attribute helps ensure that pests are eliminated more comprehensively compared to other substances.

Other substances listed may have applications in pest control but do not serve as widely recognized fumigants. For example, carbon dioxide is more commonly used as a method for modified atmosphere storage rather than direct fumigation. Chlorine is primarily used for disinfection rather than as a fumigant, while ozone, while having some pest control properties, is generally not used in the same widespread manner as methyl bromide due to potential health risks and its short-term efficacy.