Canada proposed to phase out linuron

After a re-evaluation of the herbicide linuron, the Canadian Pest Management Regulatory Authority (PMRA) is proposing to phase out the sale and use of all linuron products in Canada. This is because an evaluation of available scientific information found that, under the current conditions of use, the human health and environmental risks estimated for linuron do not meet current standards.

Linuron is a key herbicide for both carrot and potato production in Canada. Furthermore, 25 new uses of linuron are identified in the Canadian Grower Priority Database (a database of priority needs for registration of new uses identified by growers) and many of them are identified as "high priority and no alternatives".  Based on the PMRA's records, a total of eight linuron products are registered under the authority of the Pest Control Products Act, including three technical grade active ingredients and five commercial class end-use products. Of the five commercial class end-use products, three are formulated as suspensions and two as wettable granules (one of which is in water soluble bags). No domestic class end-use products containing linuron are registered in Canada. Stakeholder feedback to date suggests linuron is a key use in carrot and potato production and a future priority in herb and spice production. The number of alternatives for use on some of the minor crops is very limited.

Due to the risk concerns identified, mitigation measures and refinements were considered in the aggregate assessment. However, even with the use of refined estimates based on the mitigation scenario where all crops except those with the lowest rates (wheat, barley, and oats) are removed, the aggregate exposure from food and drinking water remains of concern.

Non-cancer risk estimates associated with applying, mixing and loading activities for wheat, oats etc. reached the target MOEs provided mitigation measures such as additional engineering controls, PPE and restrictions on amount handled per day are also considered. The restricted-entry intervals (REIs) required to mitigate post-application risk range from 21 to 74 days and may not be agronomically feasible. The PMRA also considers linuron poses risks to both terrestrial and aquatic organisms.

The PMRA will accept public comment for this proposed re-evaluation decision until September 25th.