Which of the following materials is prohibited from use or storage aboard ship?

Methyl bromide is prohibited from use or storage aboard ships due to its classification as a hazardous material with significant health risks. It is a colorless gas that can be highly toxic, causing respiratory issues and other serious health effects upon exposure. Additionally, methyl bromide has been linked to ozone depletion, making it subject to stringent regulatory controls.

The other materials listed may have restrictions and require careful handling, but they are not outright banned. For instance, bleach slurry and high-test hypochlorite are often used for sanitization, while sodium bisulfite can be utilized in specific processes. Understanding the safety and environmental implications of these chemicals is essential in maintaining safety standards on ships.