Tort Question - is this Negligence or Nuisance?

Hi all

I'm really stumped by an exam question from a recent past paper - can't figure out whether it is referring to negligence with a novus actus and or a nuisance re interference with enjoyment of land. Clearly there is a question in there about pure economic loss. Maybe all of the above? Is the answer obvious to anyone? I feel like I must be missing something obvious. As it stands I suppose I would advice on negligence, nuisance, novus actus (re neg), and pure economic loss. I'm wondering if I'm falling for a red-herring by even entertaining one of these?

WeHaul Transport Ltd is a haulage firm engaged in the transport of a wide range of goods, including toxic chemicals. Recently, a significant quantity of caustic material leaked from one of its trucks while it was moving very slowly in heavy traffic (including a number of periods when it was stopped entirely for several minutes). It transpires the leak was caused by interference with the truck's goods tanker by a vandal. The leak caused extensive damage to the road surface and left a significant amount of contaminated material on the ground. As a result the street on which it occurred was closed to traffic for a week while repairs and a clean-up were carried out.

Budget Supermarket occupies most of one side of the street that was closed and the entrance to the carpark is on that street, as is the access point for the delivery vehicles. Although the shop did have to close down, it conducted very limited business during the period of clean-up and repair.

Advise Budget Supermarket as to any cause of action it may have in tort against WeHaul, including any constraints on liability.