Amendment note below.
Provided, That any transaction carried out under the authority of this subsection shall be evidenced in writing. Whenever the head of any executive agency determines that the remaining storage or shelf life of any medical materials or medical supplies held by such agency for national emergency purposes is of too short duration to justify their continued retention for such purposes and that their transfer or disposal would be in the interest of the United States, such materials or supplies shall be considered for the purposes of section 483 of this title to be excess property. In accordance with the regulations of the Administrator, such excess materials or supplies may thereupon be transferred to or exchanged with any other Federal agency for other medical materials or supplies. Any proceeds derived from such transfers may be credited to the current applicable appropriation or fund of the transferor agency and shall be available only for the purchase of medical materials or supplies to be held for national emergency purposes. If such materials or supplies are not transferred to or exchanged with any other Federal agency, they shall be disposed of as surplus property.