The 406 is closed in both directions in St. Catharines after a leak of hydrochloric acid.
OPP Sgt. Kerry Schmidt says a transport truck started leaking the acid onto the highway at about 12:30 p.m. in the north bound lanes of the highway.
The highway is closed between Glendale and Westchester. Detours are in place.
9,000 kilograms of the acid needs to be offloaded before the highway can reopen.
Clean up crews are expected to be on scene for the rest of this afternoon into the evening.
Schmidt says it would be a good idea to avoid highway 406.
Roads around the closure are packed full of cars trying to get to their destination.
No one was hurt, and St. Catharines Fire says there is no threat to public safety in the area around the leak.
Hydrochloric acid is the water-based solution of hydrogen chloride gas, and is used as a bleaching agent, in food, textile, metal, and rubber industries.
Update on road closure - #Hwy406 between Westchester and Glendale closed in both directions due to hydrochloric acid spill. pic.twitter.com/wwX8SppdAx
— OPP Highway Safety Division (@OPP_HSD) May 11, 2022