K-REACH 2025 Amendments: New Thresholds, Hazard Categories, and Compliance Obligations

Introduction

To align with Korea’s evolving chemical management framework, the Act on the Registration and Evaluation of Chemical Substances (K-REACH) has undergone a series of significant amendments in 2025. These updates reshape core mechanisms such as new substance notification thresholds, hazard determination standards, and interlinkages with the Chemical Control Act (K-CCA) and the Occupational Safety and Health Act (K-OSHA).

To help companies navigate this regulatory shift, REACH24H Consulting Group summarizes below the most important policy changes and compliance implications — focusing on new substance notification, “unconfirmed hazardous substances,” the new classification of human and environmental hazards, and related updates under the three key chemical regulations.

New Substance Notification Thresholds

Starting January 1, 2025, Korea has raised the annual tonnage threshold for new substance registration under K-REACH:

This adjustment means substances manufactured or imported below 1 ton per year will only require notification, reducing administrative burdens for low-volume chemicals.

Unconfirmed Hazardous Substances

A new category, “unconfirmed hazardous substances,” now applies to chemicals that have been notified or registered but lack sufficient data to determine their hazard properties (excluding polymers).

Key test items under OECD guidelines include:

• Acute oral or inhalation toxicity (OECD TG 423/403)

• Mutagenicity or in vitro chromosomal aberration tests (OECD TG 471/473)

• Acute aquatic toxicity (fish, daphnia, algae) (OECD TG 201/202/203)

• Biodegradability (OECD TG 301)

Effective date: August 7, 2025 — applicable to new substance notifications submitted on or after this date.

If a substance meets any of the above “unconfirmed” criteria, the registration certificate will state:

“The applicant has confirmed this substance as an unconfirmed hazardous substance.”

Such substances must be managed in accordance with safety guidelines, treated as hazardous for human health/environment, and their information (e.g., MSDS) must be communicated to downstreams.

New Hazard Classification: Human and Environmental Hazardous Substances

From August 7, 2025, the former category of “toxic substances” under K-CCA is officially replaced by a more detailed framework:

Official Publication of the Updated “Human and Environmental Hazardous Substances” List

The Korean Ministry of Environment (MoE) has officially released the updated list of Human and Environmental Hazardous Substances. The key changes are summarized as follows:

• Reclassification of existing toxic substances:
  The 1,246 substances previously designated as “toxic substances” under the former system retain their original substance IDs but are now reclassified according to the new hazard categories. In addition, 19 substances that no longer meet the revised hazard determination criteria have been removed from the list (e.g., ethyl acetate, CAS No. 141-78-6).

• Subdivision by compound type:
  In cases where salts or derivatives of a given substance share the same base ID, sub-identifiers are now introduced to distinguish between variants — for example, among silver salts as shown below.

• Multiple hazard classifications with varying thresholds:
  For substances possessing more than one hazard type, different mixture concentration thresholds are assigned for each classification. For instance, a mixture containing 1% silver nitrate is classified as an environmental hazardous substance, whereas a mixture with ≥10% silver nitrate is classified as both environmental and human acute hazardous.

Example: Classification of Hazardous Substances (Silver Salts)

Note: The classification thresholds reflect Korea’s enhanced hazard differentiation approach under the 2025 K-REACH framework. Substances with overlapping hazard profiles are now subject to category-specific labeling and risk management requirements.

• Search the updated database (English version)

Alignment with Related Regulations

Under the Chemical Control Act (K-CCA)

To synchronize with K-REACH, the K-CCA has introduced transitional measures:

• Domestic companies that distribute or use newly designated human/environmental hazardous substances or substances in mixtures for which the specified threshold is reduced before January 1, 2026 may benefit from a grace period.

• After this date, no grace period applies for newly introduced substances.

Special note: For mixtures containing benzene (CAS 71-43-2) at 0.1–1%, the grace period is extended by an additional two years.

Under K-OSHA: MSDS and Communication Updates

From August 7, 2025, MSDS formats must reflect the following updates:

(1) For Unconfirmed Hazardous Substances

• Information must appear under Section 15 (Regulatory Information).

• Includes substance identifiers (CAS No.), confirmation of “unconfirmed” status, and missing test endpoints.

• Must be provided to downstreams immediately after receiving the notification certificate.

(2) For Human/Environmental Hazardous Substances

• Update Section 15 (2) “K-CCA” and Section 15 (3) “K-REACH” to reflect new substance classifications.

• Old MSDS templates can be used until June 30, 2026 if updated accordingly; from July 1, 2026, only new versions are valid.

Substance Confirmation (LOC) Version Updates

As of 2025, three official LOC formats have been released:

Key Takeaways for Industry

The 2025 K-REACH reform represents a major structural upgrade in Korea’s chemical management system — moving toward a more data-driven, risk-based, and harmonized approach.

REACH24H Consulting Group advises companies to:

• Review their substance inventories against the new thresholds and classifications.

• Assess whether any materials fall under the new “unconfirmed” or “human/environmental hazardous” categories.

• Update internal compliance procedures, MSDS templates, and supply chain communication in advance.

For questions about specific substance classification, registration procedures, or grace period eligibility, please contact REACH24H Consulting Group for expert regulatory support.