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

Introduction

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.

For businesses placing chemicals on the Korean market, these amendments should be reviewed together with K-REACH registration, Korea CCA compliance, Korean MSDS submission and CBI application, and downstream supply chain communication requirements.

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

Companies should not treat the higher threshold as a complete exemption. Substance identity, annual volume, use scenario, polymer status, hazard data availability and downstream communication obligations should still be reviewed before manufacturing or importing new substances into Korea.

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, including fish, daphnia and algae (OECD TG 201/202/203);

• Biodegradability (OECD TG 301).

Effective date: August 7, 2025. The category applies to new substance notifications submitted on or after this date.

Such substances must be managed in accordance with safety guidelines, treated as hazardous for human health and/or the environment, and their information, including MSDS information, must be communicated to downstream users.

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. The new system distinguishes human acute hazardous substances, human chronic hazardous substances and environmental hazardous substances.

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, such as 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.

• 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)

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.

Companies can search the updated database through the K-REACH online system where available.

Alignment with Related Regulations: 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.

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).

• The information includes substance identifiers, such as CAS No., confirmation of “unconfirmed” status, and missing test endpoints.

• The information must be provided to downstream users 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.

• Review whether additional obligations apply under K-CCA, K-OSHA, MSDS submission, CBI application, LOC and import declaration requirements.

How REACH24H Can Help

REACH24H provides Korea chemical regulatory compliance support for companies manufacturing, importing, distributing or using chemicals in Korea. Our services cover K-REACH registration and notification, K-CCA compliance, Korean MSDS submission, CBI application, supply chain communication and compliance gap assessment.

Conclusion

The 2025 K-REACH amendments bring substantial changes to Korea’s chemical compliance framework. While the increased new substance threshold may reduce the administrative burden for low-volume chemicals, the new unconfirmed hazardous substance category and human/environmental hazardous substance framework introduce new obligations for hazard communication, MSDS updates, LOC management and K-CCA compliance.

Companies should review their substance inventories, identify affected substances and mixtures, update MSDS and supply chain communication procedures, and confirm whether transitional grace periods or new compliance deadlines apply.

Recommended Reading

• K-REACH Amendments: New Toxic Substance Classifications and Compliance Guideline

• Understanding New Chemical Registration Changes Under the K-REACH Amendment

• K-REACH: South Korea Updates New Chemical Substances Hazard Assessment Results

• K-REACH Compliance Services

• Korean MSDS Submission & CBI Application Service

• Korea CCA (Chemical Control Act)

Official References

• Korea Law Information Center

• Ministry of Environment, Republic of Korea

• K-REACH Online System

• Korea Chemicals Management Association (KCMA)

• Ministry of Employment and Labor, Republic of Korea