DHS did not complete an assessment of the security value of the Transportation Worker Identification Credential (TWIC) program as required by law. This occurred because DHS experienced challenges identifying an office responsible for the effort. As a result, Coast Guard does not have a full understanding of the extent to which the TWIC program addresses security risks in the maritime environment. This will continue to impact the Coast Guard’s ability to properly develop and enforce regulations governing the TWIC program. For example, Coast Guard did not clearly define the applicability of facilities that have certain dangerous cargo in bulk when developing a final rule to implement the use of TWIC readers at high-risk maritime facilities. Without oversight and policy improvements in the TWIC program, high-risk facilities may continue to operate without enhanced security measures, putting these facilities at an increased security risk. In addition, Coast Guard needs to improve its oversight of the TWIC program to reduce the risk of transportation security incidents. Due to technical problems and lack of awareness of procedures, Coast Guard did not make full use of the TWIC card’s biometric features as intended by Congress to ensure only eligible individuals have unescorted access to secure areas of regulated facilities. During inspections at regulated facilities from FYs 2016 through 2017, Coast Guard only used electronic readers to verify, on average, about one in every 15 TWIC cards against TSA’s canceled card list. This occurred because the majority of the TWIC readers in the field have reached the end of their service life. Furthermore, the Coast Guard’s guidance governing oversight of the TWIC program is fragmented, which led to confusion and inconsistent inspection procedures. This resulted in fewer regulatory confiscations of TWIC cards. The Department concurred with our four recommendations, and described the corrective actions it is taking and plans to take.