Notwithstanding any other provision of this article, the Chief Procurement Officer or the head of a purchasing agency may make emergency procurements when there is a threat to public health, welfare, or safety under emergency conditions, as defined by rule. Emergency procurements made under this section shall be made with as much competition as is practicable under the circumstances. The authority to make emergency procurements may not be delegated. A written determination of the basis for the emergency and for the selection of the particular contractor shall be included in the contract file.