Recently, the UK Health and Safety Executive (HSE) has issued an important announcement updating the regulatory requirements for the two pesticide active substances flusulfuron and aminopyralid.

Regarding the herbicide active substance flusulfuron, the HSE has canceled the previous restriction that “the same plot is limited to one use every three years, with a maximum dose of 20 grams of active substance per hectare”. This decision has been approved by the relevant UK authorities and means that plant protection products containing flusulfuron can be used in the UK in a more flexible manner, subject to compliance with assimilation regulation No 1107/2009.

At the same time, the HSE has adjusted the requirements for the original drug specification for aminopyralid. based on the results of the latest scientific assessment, the minimum purity of the prodrug has been raised to ≥960g/kg and for the first time a maximum limit of 1 mg/kg (0.0001% w/w) has been set for the associated impurity hydrazine, at which the HSE confirms that hydrazine poses no toxicological risk. As existing products already meet the requirements of the new standard, this adjustment will be implemented straight away without the need for a transition period.

These two updates reflect the efforts of the UK pesticide regulatory authorities to optimize regulatory practices while ensuring the safety of pesticide use. These adjustments will provide a clearer technical basis for the production and use of relevant products.