In case of any emergency arising from any unforeseen causes, including delay by contractors, delay in transportation, breakdown in machinery, unanticipated volume of work, or upon the declaration of a state of emergency by the Governor, the authority shall have power to purchase in the open market any necessary supplies, materials, or equipment for immediate delivery to any agency. A report on the circumstances of the emergency and the transactions thereunder shall be duly recorded in a book or file to be kept by the authority.