Which of the following is one of the four requirements set by the hazard communication standard?

The requirement for labels for hazardous substances is a critical element of the Hazard Communication Standard (HCS). This standard, established to ensure that workers are informed about the hazards they may encounter, mandates that all hazardous substances must be properly labeled. Labels serve as a key tool in communicating essential safety information regarding the hazards associated with chemical substances. They typically include pictograms, signal words, hazard statements, precautionary statements, and the identity of the chemical, which collectively help to educate and protect employees from potential risks under working conditions.

Incorporating clear labels helps to foster a safer workplace by ensuring that all individuals can identify hazardous materials easily and understand the necessary precautions to take when handling them. This requirement is vital for compliance and for minimizing the risk of accidents or exposure to hazardous substances.

Other requirements outlined by the standard do exist, yet they do not pertain directly to labeling, which solidifies option B as central to effective hazard communication.