Final answer:
A tank should be removed from service if it has structural damage, unrepaired leaks, or fails to meet safety standards and poses environmental risks.
Step-by-step explanation:
There are several conditions that could justify the removal of a tank from service. If a tank exhibits structural damage such as deep corrosion, cracking, or deformation, it may compromise its integrity and safety. Another reason to remove a tank from service would be the presence of unrepaired leaks which can lead to loss of content and could be hazardous depending on the material contained within the tank.
Additionally, tanks must be taken out of service if they do not comply with legal or industry safety standards, which may include regular inspections and maintenance schedules. Environmental concerns also play a role; a tank may need to be decommissioned if it poses a risk of contaminating the surrounding environment, for example, by leaching harmful substances into the ground or water sources.