The Second Supplementary Existing Chemical Substance Nomination (Second Supplementary ECN, a.k.a SSECN) will open on 1 Jun 2014. The ECSI is the basis on which Taiwan will enhance its national chemical management by prescribing the requirements for registration, hazard and risk assessment. Taiwan CLA concluded the ECN and First Supplementary ECN (SECN) respectively on 31 Dec 2010 and on 31 Aug 2012. Through the ECN and the SECN, Taiwan’s national existing chemical substance inventory (ECSI) has been updated to include approximately 79,000 substances. The SSECN is the last chance to supplement the ECSI. New substances, (those excluded from the ECSI), should be registered from 11 Dec 2014 with the implementation of the revised TCSCA.