On September 18, 2024, a herbicide spill on U. S. 2 in Monroe caused significant disruption after a semitruck collided with a pickup truck towing a trailer, spilling 15 to 20 gallons of agricultural herbicides. Snohomish Regional Fire and Rescue quickly responded to contain the hazardous materials, with the state Department of Ecology overseeing the cleanup. The incident resulted in heavy traffic congestion as vehicles were diverted to alternative routes, including Roosevelt Road and Fryelands Boulevard, with backups reported to Westwick Road.

The highway was reopened around 12:45 p. m. , restoring normal traffic flow. This incident underscores the importance of safety measures in transporting hazardous materials to protect the environment and public safety.