In which circumstance can pesticides stored in service vehicles be left unattended?

The correct choice highlights that pesticides stored in service vehicles can be left unattended only when the vehicle is locked and inaccessible. This guideline is crucial for ensuring safety and compliance with pesticide regulations. A locked vehicle minimizes the risk of unauthorized access, which could lead to accidental exposure or misuse of the pesticides. Pesticides are hazardous materials that require careful handling and storage to prevent incidents that could affect public health or the environment.

While other options suggest valid considerations, such as securing the location or ensuring minimal foot traffic, they do not provide the definitive safeguard of restricting access that locking the vehicle does. Regulatory frameworks emphasize that locked storage prevents unintentional access and serves as a strong deterrent against theft or vandalism. It’s essential to maintain rigorous precautions for storing pesticides, reflecting best practices in safety management.