China's Taiwan Region to Release Second List of Existing Chemical Substances Requiring Registration

On May 21, 2026, the Chemical Substance Management Agency of the Ministry of Environment of Taiwan convened a consultation meeting for enterprises regarding the planning of the second batch of Priority Existing Chemical Substances (PECs) designated for supplementary data submission. The meeting presented relevant plans for launching the registration of these PECs. The session covered four main topics: the development history of existing chemical substance registration, substance screening and management framework, exposure information and assessment management, and the second-batch PEC substance list.

I. Development History of Existing Chemical Substance Registration

In 2016, the first phase of registration for existing chemical substances in the Taiwan region was launched. Subsequently, in 2020, standard registration for the first batch of 106 PEC substances was initiated, requiring submission of substance characteristic information along with hazard and exposure assessment data. By the end of 2024, registration of characteristic data for the first-batch PEC substances was completed. Starting the following year, the designated deadline registration for hazard and exposure assessment data of the first-batch PEC substances officially began. Recently, the environmental authorities of the Taiwan region launched the registration of the second batch of PEC substances and their supplementary data items.

Compared to the first batch, the registration application materials for the second batch of PEC substances are more aligned with the current operational realities of businesses in the Taiwan region. Therefore, registration data will serve as the starting point, with annual updates thereafter.

The Chemical Administration proactively collects substance hazard information and identifies data gaps. Priority is given to filling hazard characteristic data using alternative testing methods, etc. Where deficiencies remain, enterprises are required to complete essential information through joint registration.

Enterprises submit use and exposure information, while the Chemical Administration conducts risk assessments to determine if risks are controllable. Based on the risk assessment results, tiered risk management measures are developed.

II. Substance Screening and the Second-Batch PEC Substance List

Based on the annual declaration data from the past five years, the environmental authorities of the Taiwan region screened and compiled a list of substances with an annual manufacture or import volume of 1 ton or more, yielding a total of 11,287 substances.

After cross-referencing with authorization lists, high-concern substance lists, endocrine disruptor assessment lists, PBT assessment lists, and the second-stage list of the endocrine disruptor screening program, the authorities preliminarily identified 28 candidate existing chemical substances for assessment. This list was publicly announced in November 2025 for public consultation. After reviewing the physical/chemical, toxicological, and ecotoxicological information of these 28 substances, and comprehensively considering their uses and hazard/exposure characteristics, nine substances were determined as the second-batch PEC substances requiring supplementary data (see Table 1).

Table 1: Uses and Exposure Information for the Second Batch of Designated Existing Chemical Substances

Category	Substance Name	Major Hazards and International Management Status	Management Status in Taiwan Region
Hazards arising from impurities	Isobutane (75-28-5)	① Not inherently highly hazardous, but if butadiene impurity concentration reaches ≥0.1%, must be classified as Carcinogen Cat. 1A, Germ Cell Mutagen Cat. 1B; subject to multiple EU restrictions; not allowed for general public or consumer use. ② Ozone precursor (VOC); many countries have emission regulations. ③ Used as aerosol propellant; a pressurized gas, flammable; many countries have regulations.	Common uses: Refrigerant, aerosol propellant, fuel, organic synthesis intermediate. Regulated under: VOC Air Pollution Control and Emission Standards; Priority Managed Chemicals (Article 2, Item 3 – chemicals with threshold quantities); Public Dangerous Goods and Flammable Pressurized Gas Manufacturing, Storage, and Handling Site Standards and Safety Management Regulations; Labor Safety Rules for High-Pressure Gases.
	Hydrotreated heavy naphthenic distillate (petroleum) (64742-52-5)	① If extractables by IP346 DMSO extraction method >3%, must be classified as Carcinogen Cat. 1B; subject to multiple EU restrictions. ② Japan classifies low-refined oils as Carcinogen Cat. 1A; highly refined oils are not classified. ③ US, Canada, and Concave assess as base oil; typically highly refined with PAH content mostly <3%.	Common uses: Lubricants, base oils, metalworking fluids, other functional oils. No direct substance-specific regulation; managed under Water Pollution Control Act (oils/fats).
	Solvent-refined heavy paraffinic distillate (petroleum) (64741-88-4)
	C20-50 hydrotreated neutral oil-based lubricant (petroleum) (72623-87-1)
Carcinogenic oils	Coal tar (8007-45-2)	① Carcinogen Cat. 1. ② Strict EU controls: ≥0.1% not allowed for general public or consumer use. ③ Listed as hazardous substance under US CERCLA; release reporting required. ④ Priority assessment chemical under Japan's CSCL; detailed use data required; workplace exposure standards exist.	Common uses: Wood preservation, chemicals/materials feedstock. Regulated under: CNS 14495 for wood preservatives; Banned in cosmetics; Water Pollution Control Act (facilities/monitoring to prevent groundwater contamination); Air Pollution Control Act (HAPs – carcinogenic PAHs); Priority Managed Chemicals (Article 2, Item 2 – CMR Cat. 1); Standards for Prevention of Hazards from Specific Chemical Substances (Category C specific managed substances).
	High temperature coal tar (65996-93-2)	① Carcinogen Cat. 1A, Mutagen Cat. 1B, Reproductive Toxicant Cat. 1B. ② EU Authorization List; after sunset date (Oct 4, 2020), only authorized uses permitted (mainly specific industrial uses, e.g., carbon electrodes for aluminum smelting). ③ US and Japan have occupational exposure standards (coal tar pitch volatiles).	Common uses: Electroplating/pharmaceutical raw materials, insulating fillers. Regulated under: Carcinogenic PAHs as HAPs; Stationary Source Air Pollutant Emission Standards; Permissible Exposure Limits for Workplace Environments.
	Vacuum residue oil (64741-56-6)	① IARC Group 2B carcinogen, but EU registration data does not classify it as such; EU has not planned further evaluation. ② No management regulations found in US or Japan.	Common uses: Asphalt for road construction, lubricant or other oil production. Managed under: Air Pollution Control Act (particulates); Water Pollution Control Act (suspended solids, oils/fats); Permissible Exposure Limits for Workplace Environments (total dust, respirable dust).
Substances used as intermediates that may still cause exposure if reaction incomplete	4-tert-Butylbenzoic acid (98-73-7)	① Reproductive toxicant Cat. 1B. ② Subject to multiple EU restrictions; ≥3% not allowed for general public or consumer use. ③ EU ARN indicated no further action needed due to intermediate use and existing measures from harmonized classification. ④ Occupational exposure standards in some EU countries (Netherlands, Switzerland, Germany). ⑤ Japan allows use in food equipment, containers, packaging.	Common uses: Organic synthesis intermediate, precursor for additives in polymers/resins. Regulated under: Priority Managed Chemicals (Article 2, Item 2 – CMR Cat. 1).
	2-Hydroxy-2-methylpropionitrile (Acetone cyanohydrin) (75-86-5)	① Acute aquatic toxicity Cat. 1. ② Subject to multiple EU regulations (e.g., marine environment, waste directives). ③ Listed as hazardous substance under US CERCLA; release reporting required. ④ Japan lists as deleterious substance, water/soil pollutant.	Common uses: Organic synthesis intermediate; products used in pesticides, pharmaceuticals, polymer industry. Regulated under: Water Pollution Control Act (cyanides); Air Pollution Control Act (cyanides, HCN); Permissible Exposure Limits for Workplace Environments (cyanides, HCN); Priority Managed Chemicals (Article 2, Item 3 – chemicals with threshold quantities).

III. Priorities for Subsequent Assessment and Management

For the subsequent assessment planning of the second-batch PEC substances, the environmental authorities of the Taiwan region will draw lessons from the implementation experience of the first-batch standard registration. The approach will be adjusted as follows: the Chemical Administration will first review international information, establish hazard data, collect exposure information from registrants, and then proceed with assessment and management.

Data Collection	Core task: Enterprises voluntarily submit substance use and exposure information. Exposure information: Actual operational data such as impurities, downstream use conditions. Hazard information: Prioritize alternative testing methods; where necessary, multiple enterprises jointly conduct tests to avoid duplicate resource investment.
Risk Assessment	Initial assessment: Using a modified TRA tool. Dynamic adjustment: Confirm whether risks are controllable based on assessment results, and revise accordingly. Criteria for controllable risk: Substance largely exported; only industrial uses with existing management regulations; small number of operating enterprises; downstream risks identifiable and controllable; other cases.
Management Communication	Case-by-case management: Develop individual management plans for low-volume or specific risk use Inclusion in supply chain management as a concerned chemical substance.

CIRS Chemical Registration Technical Team will continue to follow and study the progress of chemical registration regulations in the Taiwan and provide professional regulatory interpretation and compliance advice to enterprises concerned about chemical substance management policies in the Taiwan.

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