Chemical leak closes Interstate 65 south of Gary

A chemical leak that left five people complaining of breathing problems led to the shutdown of a section of Interstate 65 on Thursday, authorities said.\nA 17-mile stretch of the interstate was closed in both directions about 20 miles south of Gary as a precaution at about 10:30 a.m. as hazardous materials responders prepared to neutralize the chemical, sodium hydrosulfite, said Mike Higgins, a spokesman for the Lake County Sheriff's Department.\nThe methods they planned to use could result in an explosion and a large cloud of gas, Higgins said.\nSodium hydrosulfite is a flammable solid that can ignite on contact with moisture such as rain, said Dan Miller, a hazardous materials chemist at Purdue University. Such a reaction produces sulfur dioxide, which he said can poisonous if inhaled.\nTelevision helicopter images showed a backhoe poking holes into a white semitrailer at the edge of the truck stop parking lot surrounded by a freshly dug trench. Workers wearing protective suits performed the work in a parking lot wet from rain.\nThe highway closed about nine hours after the first reports of a gas leaking from a semitrailer at the Pilot Travel Center, a truck stop along Indiana 2 near Lowell, Higgins said. Indiana 2 also was closed.\nA truck had been hauling 40,000 pounds of sodium hydrosulfite, and some of the dry chemical apparently spilled from one of the trailer's containers and mixed with rainwater, Higgins said.\nThe water turned the chemical into a gas and a fog began to develop, Higgins said.\nA police officer who moved truck drivers in the area about 50 yards from the cloud was among five people treated for respiratory discomfort, Higgins said.\nPurdue's Miller said sodium hydrosulfite is a reducing agent used in the textile, leather and pulp and paper industries and in water treatment and chemical processing.\n"It's pretty nasty stuff. I'm glad I'm not cleaning it up," Miller said.