To require the Secretary of Homeland Security to prepare a comprehensive security assessment of the transportation security card program, and for other purposes.

Essential Transportation Worker Identification Credential Assessment Act Directs the Secretary of Homeland Security (DHS) to submit to Congress and the Comptroller General (GAO) a comprehensive assessment of the effectiveness of the transportation security card program at enhancing security and reducing security risks for maritime facilities and vessels. Requires the assessment to be conducted, to the extent practicable, by a national laboratory within the DHS laboratory network or a maritime security university-based center within the DHS centers of excellence network. Directs the Secretary to submit to Congress a corrective action plan responding to the assessment which: (1) includes an implementation plan with benchmarks, and (2) shall be considered in any DHS rulemaking with respect to the transportation security card program. Directs the Comptroller General, within 120 days after the corrective action plan is issued, to: (1) review the extent to which it implements the recommendations of the national laboratory or the maritime security university-based center and of the Comptroller General, and (2) inform Congress as to the plan's responsiveness to such recommendations. Prohibits the Secretary from issuing a final rule requiring the use of transportation security card readers until: (1) the Comptroller General informs Congress that the submission is responsive to the GAO recommendations, and (2) the Secretary issues an updated list of transportation security card readers that are compatible with active transportation security cards. Requires the Comptroller General to report to Congress on implementation of the plan at least 18 months after it is issued, and every 6 months thereafter for the ensuing 3-year period. Declares that no additional funds are authorized to carry out this Act. Requires this Act to be carried out using amounts otherwise available for the purpose.