A 10-year-old boy was taken to hospital after playing with a canister of chemicals, dumped behind a warehouse.
Emergency services were called to Deepdale Mill Street at 3.10pm yesterday, after initial reports that the boy suffered facial burns.
The road was cordoned off while the boy was treated by paramedics, and firefighters made the scene safe.
Preston crew manager Ian Armistead said: “A child has found some drums of sodium hydroxide at the rear of a building and has opened one of the tubs.
“He’s got some of the powder on himself and has had to be taken to hospital for a skin irritation, but he’s okay.
He added: “The road closures look dramatic, but it was just to keep the public safe and out of the way while the clean-up operation took place.”
Firefighters wearing breathing apparatus discovered 125 kilograms of the chemical in drums, and had to call in a specialist removal team.
Sodium hydroxide is used in the manufacture of pulp and cleaning products.