A tractor trailer carrying tetrapotassium pyrophosphate overturned at the 43-mile marker while driving southbound on I-65 Wednesday afternoon. The chemical leaked from a valve, causing traffic to be held back half-a-mile in each direction until the chemical was identified. Photo by Miranda Pederson

A tanker truck carrying corrosive liquid overturned on Interstate 65 South Wednesday afternoon near Smiths Grove, causing a shutdown on the road for several hours. At about 1:30 p.m. the driver of a tanker truck carrying tetrapotassium pyrophosphate solution, a corrosive liquid used in manufacturing and water treatment facilities, swerved to avoid what he thought was a tire in the road near mile marker 42, Kentucky State Police Trooper Michael Concaugh said. The driver, Rigoberto Gonzalaz Sr., 47, of San Benito, Texas, was taken by ambulance to The Medical Center where he was treated for a back injury, Concaugh said. Hospital spokesman Bill Oldham said Gonzalaz was treated and released Wednesday night. When the truck overturned, the tankers contents began seeping through an overflow cap, said Jim Potts, assistant chief of the Smiths Grove Fire Department .Theres very little spillage, Potts said. Theyve dyked all the drains so nothing can leak out. Theres a pond over there across the interstate, and they wanted to make sure it doesnt drain into it. Both sides of I-65 were shut down at about 2 p.m. When Potts first arrived at the accident site, he and other emergency service providers were told the truck was carrying sulfuric acid. Firefighters, clad in hazardous materials suits, approached the truck to try to determine the extent of the spillage. Along with the Smiths Grove volunteer firefighters and KSP, representatives from the Department of Emergency Services, the state Cabinet for Natural Resources and Environmental Protection, the state Fire Marshalls office, the Kentucky Highway Department and the Kentucky Motor Vehicle Enforcement office responded to the accident. Traffic was shut down from Exit 38 to Park City, Potts said. We evacuated everybody within a half a mile, Potts said. Once officials determined that the substance wasnt as hazardous as they originally thought, traffic was gradually allowed back on the interstate. The driver wasnt able to tell us what he was hauling because he couldnt get to the bill of lading inside the cab, Concaugh said. Gonzalaz was driving for Mission Petroleum Carrier of Houston. Another tanker from Nashville was called to offload the tankers contents before the badly damaged truck could be removed. More than two hours after the initial call, the northbound lanes were reopened. The southbound lanes remained closed until about 6:30 p.m.First Response, an environmental cleanup company, remained on the scene overnight.