Amount from Settlement Taxable? California v. Vitol

From what I have read, settlement amounts can be taxable or non-taxable depending on the nature of the claim.

 

In California v. Vitol, people received settlement amounts due to "overpaying for gas". To me, it seems like a refund or return of money. So unless gas was deducted as a business expense in past returns, the settlement amount should not be taxable? Is this correct?