VALLEJO (KRON) — Crews are cleaning up a chemical spill in Vallejo after a delivery truck spilled aluminum sulfate on the way to a water treatment plant on Wednesday morning, according to fire spokesman Stuart Cole.

Cole said the spill closed streets.

The contractor’s truck, which is unaffiliated with the city, was making a delivery of the chemical used in water treatment to the Fleming Hill Water Treatment Plant around 8:50 a.m., Vallejo fire engineer Danny Gutierrez said.

Fire crews found the chemical in a dry dormant state in a one-mile area between B.W. Williams Drive and Broadway Street across to Tuolumne Street and Phoenix Circle near the Fleming Hill Water Treatment Plant, Gutierrez said.

Stuart Cole, the Vallejo Public Works Department’s water treatment superintendent, said the chemical was in liquid form when it spilled but dried to a white powder on the roads.

Cole said the spill was between 6 and 12 inches wide and about a quarter- to half-mile long.

Public works crews have barricaded storm drains to keep the chemical out of the storm drain system. The chemical did not contaminate the city’s water supply, Gutierrez said.

The cleanup is expected to take until 6 p.m., Gutierrez said.Bay City News contributed to this report.