GreenLane Maritime Cargo Security Act

GreenLane Maritime Cargo Security Act - Directs the Secretary of Homeland Security to submit to Congress a comprehensive strategic plan to enhance international supply chain security for all modes of transportation by which containers arrive in, depart from, or move through U.S. seaports.

Directs the Secretary to develop and implement a plan for improving the Automated Targeting System for identifying high-risk containers moving through the international supply chain.

Amends the Homeland Security Act of 2002 to establish within the Department of Homeland Security (DHS) an Office of Cargo Security Policy to coordinate all Department policies and programs relating to cargo security.

Establishes minimum standards for securing containers in transit to an importer in the United States, including international standards for the security of containers moving through the international supply chain.

Requires all containers entering the United States to be examined for radiation.

Establishes the Container Security Initiative (CSI) to identify and examine maritime containers that pose a risk for terrorism at foreign ports before they are shipped to the United States.

Establishes: (1) the Customs-Trade Partnership Against Terrorism (C-TPAT) to strengthen and improve the overall security of the international supply chain and U.S. border security; and (2) a third tier of C-TPAT (Greenlane) that offers additional benefits to validated C-TPAT participants that demonstrate a sustained commitment beyond the minimum requirements for participation in C-TPAT.

Establishes a port security grant program to correct port security vulnerabilities.