Ministry of Environment Announces Draft Amendments to the List and Management of Toxic Chemical Substances

On 4 November 2025, Taiwan's Ministry of Environment (MOENV) released a draft amendment to the List of Toxic Chemical Substances and Its Management Measures.
The proposal adds the following substances as toxic chemical substances:

• Methoxychlor (CAS No. 72-43-5)
• Chlordene (Decachlorooctahydro-1,3,4-metheno-2H-cyclobuta[cd]pentalen-2-one; CAS No. 143-50-0)
• 2-(2H-benzotriazol-2-yl)-4,6-di-tert-pentylphenol (UV-328; CAS No. 25973-55-1)

The draft also specifies control concentrations and operational management measures for these substances. In addition, it strengthens management regulations for mercury and tetrachloroethylene, reinforcing Taiwan’s toxic chemical management framework.

Alignment with International Conventions

According to the MOENV, these substances are Persistent Organic Pollutants (POPs) known for their resistance to degradation, potential for long-range transport, and bioaccumulative nature, posing significant risks to human health and the environment.

The proposed amendment aligns Taiwan’s regulatory scope with the Stockholm Convention’s recent inclusion of Methoxychlor, Chlordene, and UV-328.

Classification details:

• Methoxychlor will be listed as a Class 1, Class 3, and Class 4 toxic chemical substance due to its bioaccumulation potential, persistence, and acute ecological toxicity.
• Chlordene will be listed as Class 1 and Class 4 due to its bioaccumulative and persistent nature (both with a control concentration of 0.1%).
• UV-328, which also exhibits bioaccumulation and persistence, will be classified as Class 1 and Class 4 toxic chemical substances, with a control concentration of 100%. Permitted uses are clearly defined, and threshold limits have been established in line with the EU’s POPs Regulation to ensure international consistency.

Both Methoxychlor and Chlordene will be prohibited from use, except for research, testing, and educational purposes, consistent with the Stockholm Convention.

Strengthened Controls on Mercury and Tetrachloroethylene

Mercury has been listed as a Class 1 toxic chemical substance since 1991. In line with the Minamata Convention on Mercury. The new amendment revises prohibited operations and allowable uses of mercury.

Tetrachloroethylene, listed as a Class 1 and Class 2 toxic chemical substance since 1997, will now be prohibited for use in cleaning agents. However, existing approved users may continue using it until their registered dry-cleaning equipment cycles are completed.

Traditional Measures and Industry Responsibilities

The MOENV emphasized that while new substances are being added to the list, the amendment also considers current domestic practices. Requirements include updated application procedures for permits and approvals, labeling, transportation, alarm and detection equipment, and the appointment of qualified technical and emergency response personnel. To facilitate adjustment, existing operators will be granted a transition period of one to one and a half years. The MOENV also encourages industries to identify safer substitute substances to reduce potential impacts on public health and the environment.

Public Consultation

For details of the draft amendment, please refer to the MOENV News Section (https://enews.moenv.gov.tw/) or visit the Executive Yuan Gazette Online (https://gazette.nat.gov.tw/egFront/) three days after the announcement. Comments or suggested revisions may be submitted to the Ministry of Environment within 30 days from the day following the public notice (Email: yilin.yu@moenv.gov.tw).