Tenn. Code Ann. § 67-3-416

A refund of the tax imposed by §§ 67-3-201 and 67-3-202 covering loss of gallonage due to fire, flood, storm, theft or other causes over which a vendor has no control will be made if the loss is reported to the commissioner within three (3) business days of the date of the loss, except that losses not exceeding one thousand gallons (1,000 gals.) need not be reported. With respect to all losses, the vendor shall file with the commissioner a written claim and statement explaining the occurrence of the loss within sixty (60) days of the time of loss. Negligence or any unlawful act, such as overloading a transport vehicle, excessive speed or other like act by a vendor or such vendor's agent, that is contributory to a loss, shall invalidate the claim.