Japan to Regulate Fenazaquin as Deleterious Substance under PDSCL

By Yuko Howell, Regulatory Affairs Lead, Supply Chain Team, UL Solutions

Japan’s Ministry of Health, Labour and Welfare (MHLW) has proposed an amendment to the Cabinet Order on the Designation of Poisonous and Deleterious Substances. The revision includes:

• Designation of a new deleterious substance: 4-[2-(4-tert-Butylphenyl)ethoxy]quinazoline (Fenazaquin) (CAS No. 120928-09-8) and its preparations (except those with ≤19.4% concentration).
• Removal of a formulation from the list: Preparations containing sodium chlorate (47.5 - 52.5%) (CAS No. 7775-09-9) and sodium bicarbonate (27 - 37%) (CAS No. 144-55-8), excluding powdered forms.

The MHLW is accepting public comments on the proposal until August 24, 2025. The update to the Cabinet Order is expected to be finalized in October and become effective on November 1.

Fenazaquin was found to pose a high risk of acute toxicity upon exposure, justifying its classification as a deleterious substance. Conversely, the sodium chlorate/sodium bicarbonate formulation was determined to have significantly lower toxicity, warranting its removal from the list.

Compliance implications for global suppliers

1. SDS and Labeling Requirements

Suppliers must update Safety Data Sheets (SDSs) and labels to reflect the new classification. GHS-compliant SDS and labels are currently accepted under the Poisonous and Deleterious Substances Control Law (PDCSL) and Regulations.

2. Registration Obligations

Entities manufacturing or importing deleterious substances into Japan must:

• Register with local public health authorities under the PDSCL.
• Maintain records, ensure secure storage, and display appropriate signage.

For Fenazaquin, only one manufacturer is currently expected to register, with a fee of ¥10,900 per registration in Tokyo.

Next steps

• Submit comments by August 24, 2025.
• Monitor final publication in October and prepare for enforcement starting November 1, 2025.
• Review product portfolios and update SDS, labels, and registrations accordingly.

References

• Proposed amendment to the Cabinet Order on Designation of Poisonous and Deleterious Substances  (Available in Japanese only)
• Public comment submission on the proposed amendment (Available in Japanese only)
• Preliminary Regulatory Assessment Report (Available in Japanese only)