Liquid CO2 have been set back from building enough to do the usual maintenance to the external insulation and coating. This is quite often what is done in bottling plants, for example. I know of no "safety" precautions - other than the local traffic and process conditions that are normally accounted for.
If the tank is outdoors, as you infer, I see no reason to be concerned with respect to its contents. This is an operation that has been applied world-wide for over 50 years to my knowledge. I've applied it around the world in many countries, including the USA.
Do you have any specific concerns or do you suspect anything needs especially to be done?