Which standard requires containers holding hazardous chemicals to have a visible warning label?

The Hazard Communication Standard (HCS) is the correct answer because it is specifically designed to ensure that employers and employees are informed about the hazards of chemicals they may be exposed to in the workplace. Under this standard, containers holding hazardous chemicals must have visible warning labels. These labels serve to communicate the danger associated with the contents, providing essential information to help prevent accidents and promote safe handling.

This standard is part of OSHA's regulations and aims to facilitate a safer work environment by requiring clear labeling, which includes hazard warnings, precautionary statements, and other relevant information regarding the use and storage of hazardous substances. The requirements are crucial for both understanding immediate dangers and ensuring that necessary safety measures are taken when handling these chemicals.

Other options, while relevant to workplace safety, do not specifically mandate the labeling of hazardous chemical containers. The Occupational Health Act focuses more broadly on ensuring safe and healthful working conditions, while the Safety Data Sheet provides detailed information about hazards but is not the source of labeling requirements. The Personal Protective Equipment Regulation deals with the use of protective gear rather than chemical labeling.