Which of the following situations would require immediate reporting to authorities in TDG?

Immediate reporting to authorities is crucial when there is a major leak of hazardous materials due to the serious potential risks involved. Such a situation poses a significant threat to public safety, the environment, and compliance with regulations pertaining to the handling and transportation of dangerous goods. Prompt reporting enables the appropriate response teams to take necessary actions to manage the leak, mitigate hazards, and ensure the safety of individuals in the vicinity.

In contrast, inquiries about dangerous goods, minor incidents without visible spills, or updates to shipping schedules do not necessitate immediate alerts to authorities since they do not involve the same level of risk or urgency that a major leak represents. These situations, while still relevant to the safe management of dangerous goods, do not pose an immediate threat that requires rapid intervention from regulatory bodies or emergency services.