9 C.F.R. § 146.4
(d) Each participant shall be assigned a permanent approval number by the Service. This number, prefaced by the numerical code of the State, will be the official approval number of the participant and may be used on each certificate, invoice, shipping label, or other document used by the participant in the sale of the participant's products. Each Official State Agency which requires an approval number for out-of-State participants to ship into its State shall honor this number.
(Approved by the Office of Management and Budget under control number 0579-0007)
[71 FR 56328, Sept. 26, 2006, as amended at 75 FR 10658, Mar. 9, 2010]