Federal Environment Agency upgrades phosphine oxide 6366 to water hazard class 3

The German Environment Agency (Umweltbundesamt) has upgraded the substance diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide under identification number 6366 from water hazard class (WGK) 2 to WGK 3. The general decree dated September 14, 2026, was publicly announced on Wednesday, October 14, 2026, in the Federal Gazette (Bundesanzeiger) under the official reference BAnz AT 14.10.2026 B6. Simultaneously, the authority ordered the immediate execution of the decision.

Ex officio Re-evaluation

The German Environment Agency has re-evaluated the substance ex officio and implemented the change in classification. The legal basis is Section 7(1) sentence 1 of the Ordinance on Facilities for Handling Substances Hazardous to Water (AwSV), which empowers the authority to make new decisions regarding the classification of substances and substance groups. Notification is carried out in accordance with Section 7(1) sentence 2 in conjunction with Section 6(4) sentence 1 AwSV in the Federal Gazette; the notification obligations under Section 7(2) AwSV remain unaffected.

The previous classification as WGK 2 from August 1, 2017, is withdrawn for the future. The withdrawal is based on Section 48(1) sentence 1 of the Administrative Procedure Act (VwVfG), as the classification has become unlawful due to new findings. In the opinion of the authority, the protection of legitimate expectations under Section 48(3) VwVfG does not apply, as facility operators cannot rely on the permanence of classifications due to the regulations of Section 7 AwSV.

Basis for the Upgrade

The classification is based on the following data and findings:

• Mammalian toxicity: Hazard statement H360Fd, acute oral LD50 > 2,000 mg/kg BW, four evaluation points.
• Environmental hazard: Hazard statement H411, acute aquatic toxicity 1 mg/l < LC/EC50 ≤ 10 mg/l, six evaluation points.
• Evidence of ready biodegradability: no.
• Evidence to exclude bioaccumulation potential: yes.
• Reproductive toxicity: Classification based on the harmonized EU legal classification (Index No. 015-203-00-X).

Following publication in the Federal Gazette, the classification decision can additionally be searched via the German Environment Agency website at https://webrigoletto.uba.de/rigoletto/.

Immediate Execution and Legal Remedies

Immediate execution was ordered in accordance with Section 80(2) sentence 1 number 4 of the Code of Administrative Court Procedure (VwGO). In its justification, the German Environment Agency refers to the direct impact of the classification on the construction and operation of facilities requiring a permit, as well as the public interest in legal certainty and water protection. An objection or a lawsuit against the general decrees therefore has no suspensive effect.

The general decrees become effective upon notification; this occurs on the 15th day after publication in the Bundesanzeiger (Federal Gazette), pursuant to § 41 paragraph 4 sentence 3 VwVfG (Administrative Procedure Act). An objection against the general decrees may be lodged with the Umweltbundesamt (Federal Environment Agency) based in Dessau-Roßlau within one month after notification. The signing was carried out on behalf of the agency by Süßmilch; the PDF file of the official publication is provided with a qualified electronic seal.

Significance for Plant Operators

With the upgrade to WGK 3, the stricter requirements of the highest water hazard class will henceforth apply to plants handling the substance Diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide. Operators must adapt their plant and reporting obligations to the amended classification and cannot rely on the previously applicable WGK 2. Since the decision is immediately enforceable, it takes effect regardless of any possible legal remedy proceedings.

Source: Bundesanzeiger, BAnz AT 14.10.2026 B6, Announcement of the Federal Environment Agency dated September 14, 2026 (official reference: BAnz AT 14.10.2026 B6).