On 23 March 2020 the U.S. Department of Homeland Security's (DHS) Cybersecurity & Infrastructure Security Agency (CISA) published revisions to its guidance regarding the "Essential Critical Infrastructure Workforce." One of the key updates to the CISA guidance is additional language to ensure the transportation supply chain is included within the scope of the guidance. Under the "critical manufacturing" category, the new language identifies the transportation supply chain and adds: "workers needed to maintain the continuity of these manufacturing functions and associated supply chains."