WASHINGTON, May 17 (Xinhua) -- About 3,500 people were evacuated in Lafayette, Louisiana, on Saturday after a derailed freight train began leaking acid, police said.

    Six cars of the freight train derailed early Saturday and one of them began leaking hydrochloric acid, which was believed to cause respiratory problems and skin and eye irritation.

    An estimated 8,000 to 10,000 gallons of the acid has been spilled, and homes, business and two nursing homes in a 1.6-km radius of the accident spot with an estimated population of 3,500 people were evacuated, according to the police.

    The acid sent a toxic cloud over the area, and at least five people were taken to a hospital for treatment, said Craig Stansbury, an official of the Lafayette Parish sheriff's office. "We're advising them to take enough supplies for approximately 48 hours," he said.

    The U.S. railway administration will investigate the accident.