A box truck leaking chlorine briefly shut down I-35W southbound in Minneapolis.
The rush-hour incident saw a 50-gallon barrel spill from the truck near 11th Ave. S.
Minneapolis Fire Department says the interstate was initially blocked southbound while crews worked to contain the spill, before one lane was re-opened just after 9 a.m.
The fire department said that some of the chlorine had leaked into the sewer system prior to its crews arriving, with the sewer now diked off.
The rest of the chlorine has been diluted, with a cleanup contractor on its way to the scene.
"The remaining lanes of traffic will be opened shortly," the department said.