RTC §6593.5: (a) The department, in its discretion, may relieve all or any part of the interest imposed on a person by this part under the following circumstances: (1) Where the failure to pay tax is due in whole

(a) The department, in its discretion, may relieve all or any part of the interest imposed on a person by this part under the following circumstances: (1) Where the failure to pay tax is due in whole or in part to an unreasonable error or delay by an employee of the department acting in their official capacity. (2) Where failure to pay sales or use tax was the direct result of an error or delay by a state agency that collects the tax on behalf of the California Department of Tax and Fee Administration. (b) For purposes of this section, an error or delay shall be deemed to have occurred only if no significant aspect of the error or delay is attributable to an act of, or a failure to act by, the taxpayer. (c) Any person seeking relief under this section shall file with the department a statement under penalty of perjury setting forth the facts on which the claim for relief is based and any other information which the department may require. (d) The department may grant relief only for interest imposed on tax liabilities that arise during taxable periods commencing on or after July 1, 1999.