Gallons of sulphuric acid leaked into a water course next to a Warwickshire road last night.
The spill happened at about 6pm after two 20-litre plastic drums fell from a vehicle transporting them along the A444 near Nuneaton. About 30 gallons of acid was spilt and ran into nearby drains.
Warwickshire police closed the northbound stretch of the road between Griff Island and junction three of the M6 for several hours.
A spokeswoman for Warwickshire Fire Service said the spillage did not pose any danger to public health.