TAIWAN TCCSCA REGULATORY UPDATE
Taiwan's Chemicals Administration has selected carbon black, 4,4'-methylenediphenyl diisocyanate (4,4'-MDI) and silicon carbide for the next phase of hazard and exposure assessment information under existing-chemical standard registration. Registrants that have obtained standard-registration completion numbers and fall within the authority's designation are expected to submit the required information by December 31, 2027.
The authority also plans industry briefing sessions in Kaohsiung on August 17 and Taipei on August 18, 2026. Affected manufacturers and importers should use the lead time to confirm their registration status, choose a hazard-assessment route and map actual exposure scenarios across the Taiwan supply chain.
For a broader overview of substance status, registration routes and post-registration obligations, see REACH24H's Taiwan TCCSCA and OSHA chemical registration services.
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Which Three Existing Chemicals Are Covered?
| Substance | CAS No. | Common Reference |
|---|---|---|
| Carbon black | 1333-86-4 | Carbon black |
| 4,4'-Methylenediphenyl diisocyanate | 101-68-8 | 4,4'-MDI / MDI |
| Silicon carbide | 409-21-2 | Silicon carbide / SiC |
The update follows the staged structure of Taiwan's existing-chemical registration system. Under Article 18 of the Regulations of New and Existing Chemical Substances Registration, the authority issues a completion number once an existing-substance registrant completes the information specified in Appendix 3. The registrant must then complete the Appendix 4 information proactively or by a deadline set by the authority.
The first group of 106 priority existing substances reached its main Appendix 3 deadline at the end of 2024. Taiwan later designated registrants for antimony trioxide, sulfuric acid, toluene and zinc oxide to submit hazard and exposure information by the end of 2026. The new three-substance update continues this post-registration data-supplementation process; it should not be confused with the separate planning work for a second batch of existing substances.
Who Needs to Act?
The December 31, 2027 date should not be read as a blanket deadline for every company that manufactures, imports, supplies or uses one of the three substances. The update is directed at registrants that meet the specified conditions (tonnage bands reaching Tier 2 through Tier 4 for existing chemical substance standard registration) and have already obtained a standard-registration completion number.
Each company should verify:
whether the registered substance and CAS number match the substance it manufactures or imports, including relevant identity and composition details;
which Taiwan manufacturer or importer is the statutory registrant and whether a qualified representative is involved;
the standard-registration level, completion number and any authority communication received for the substance;
whether the registered manufacture, import, formulation, use or exposure information remains accurate; and
who owns the technical data and whether the registrant has permission to use it for the supplemental submission.
For overseas suppliers, the Taiwan manufacturer or importer remains the registrant. However, the overseas data owner may need to provide substance-identity, use, volume, hazard and safe-use information. Data-access rights and confidential business information arrangements should therefore be settled before dossier work begins.
How Can the Hazard Assessment Requirement Be Met?
The Chemicals Administration plans to make hazard assessment examples available for the three substances. Registrants can use the authority's example as a reference or prepare their own hazard assessment information.
Option 1: Use the Authority-Provided Example
According to the source material, a registrant that adopts the authority-provided example does not need to prepare and submit a separate hazard assessment report. The registrant should nevertheless confirm the authority's required confirmation procedure and ensure that its substance identity and registration scope fit the example.
Option 2: Prepare a Registrant-Specific Report
A registrant that does not use the official example should complete the authority's questionnaire by December 31, 2026 and submit its independently prepared hazard assessment report by December 31, 2027.
Why the Exposure Assessment Must Reflect Actual Operations
Exposure conditions differ among registrants, even for the same substance. The exposure assessment therefore needs to reflect each registrant's actual or expected activities rather than rely solely on a common substance-level assessment.
By December 31, 2027, affected registrants should be prepared to:
update or supplement the original manufacture, import, use and exposure information relevant to the registration;
describe actual or expected manufacturing, formulation and use activities where applicable;
prepare exposure scenario descriptions that reflect operating conditions, exposure pathways and existing risk-management measures; and
check that upstream supplier information and downstream-use information are consistent with the registrant's own submission.
A generic exposure narrative can create gaps if it does not match the registrant's real process or downstream uses. Registrants should map the supply chain early and document who can confirm each use, task, exposure pathway and risk-management measure.
What Should Companies Do Before the 2027 Deadline?
Confirm scope: Check the CAS number, substance identity, registration level, completion number and any authority notice or communication.
Select the hazard-assessment route: Decide whether the authority-provided example can be used or whether a company-specific report is needed. If the latter applies, plan for the December 31, 2026 questionnaire milestone.
Map exposure scenarios: Identify manufacturing, formulation and use activities, operating conditions, exposure pathways and risk-management measures for the Taiwan registrant.
Audit the existing dossier: Compare the original registration data with current operations and identify changes, inconsistencies or missing evidence.
Secure data access and CBI arrangements: Confirm study-use rights, supplier permissions, confidentiality controls and the information flow among the overseas supplier, Taiwan registrant, representative and technical service providers.
Build an internal submission schedule: Allow time for data collection, technical assessment, translations, internal review and any authority questions rather than treating December 31, 2027 as the project start date.
How REACH24H Can Support Taiwan Chemical Registration
REACH24H supports overseas manufacturers, Taiwan importers and manufacturers, and multinational regulatory teams with Taiwan existing-chemical registration and post-registration work. For this update, support may include:
applicability, registrant-role and registration-status assessment;
data-gap analysis and testing or non-testing strategy;
hazard and exposure assessment preparation, including exposure-scenario coordination; and
dossier submission, authority communication and correction support.
Need Support with Taiwan Chemical Registration?
If your company manufactures, imports or supplies carbon black, 4,4'-MDI or silicon carbide to Taiwan, submit the substance identity, registration number, uses and available data for an initial assessment.
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