WILLARD, Ohio — A city official says authorities have contained a spill at a northern Ohio rail yard where potentially flammable liquid leaked from a railcar, prompting the evacuation of hundreds of nearby homes.

Responders and cleanup workers from transportation company CSX Corp. were at the scene today in Willard, about 65 miles southwest of Cleveland.

City Manager Brian Humphress said that liquid leaked from a 4-inch hole in a 26,000-gallon tanker for several hours before it was resealed. He says cleaning up may be a long process.

It wasn’t immediately clear what caused the leak. The liquid was believed to be styrene monomer, which is used to make various plastic and rubber products.

Residents were told overnight to evacuate an area encompassing an estimated 400 homes.