; or (ii) weekly, during a period of national emergency declared by an Act of Congress or the President, with respect to the previous week. (6) Liabilities against Fund When any agreement entered into pursuant to this section imposes any contingent liability upon the United States, such liability shall be considered an obligation against the Fund. (h) Delegation of authority The Secretary may only delegate authority under this section to the Assistant Secretary for Preparedness and Response and such Assistant Secretary may not further delegate such authority. (i) Authorization of Appropriations There is authorized to be appropriated such sums as may be necessary for fiscal year 2020 and each fiscal year thereafter for the carrying out of the provisions and purposes of this section. (j) Definitions For purposes of this section, the following definitions shall apply: (1) Critical component The term critical component includes such components, subsystems, systems, and related special tooling and test equipment essential to the production, repair, maintenance, or operation of biological, chemical, and radiological security program applications or other items of equipment identified by the Secretary as being essential to the execution of a pandemic response strategy of the United States. (2) Critical technology The term critical technology includes any technology designated by the Secretary to be essential to the execution of a pandemic response strategy of the United States. (3) Critical technology item The term critical technology item means materials directly employing, derived from, or utilizing a critical technology. (4) Domestic industrial base The term domestic industrial base means domestic sources which are providing, or which would be reasonably expected to provide, materials or services to meet national pandemic response requirements during peacetime or national emergency. (5) Domestic source The term domestic source means a business concern— (A) that performs in the United States substantially all of the