Which of the following is not required labeling under the HazCom standard?

The Hazard Communication (HazCom) standard requires that specific labeling is applied to hazardous chemicals and materials to ensure safety and provide necessary information to employees. However, certain items do not require labeling under this standard.

Hazardous waste regulated by the Environmental Protection Agency (EPA) has its own labeling requirements, which are distinct from the HazCom standard. Additionally, piping systems and fuel tanks, particularly those that are part of a vehicle, have specific regulations that guide their labeling but are not covered under the HazCom requirements.

Given these considerations, the correct answer demonstrates an understanding that the stipulations of the HazCom standard do not encompass all items and that labeling requirements can vary significantly based on regulatory guidance distinct from HazCom. Thus, it is evident that labeling for hazardous waste, piping systems, and fuel tanks in vehicles is not mandated under the HazCom standard, leading to the conclusion that all these options fall outside the standard's labeling requirements.