Missouri 168 is closed two miles north of US 61 near Hannibal because of an overturned semi. Hannibal Emergency Management Director John Hark says the truck was carrying chemicals on 168 when it went off the road. The chemical was being transported in metal reinforced plastic tanks in the trailer. Hark says the primary hazard is inhalation. It's believed the truck was on the way to BASF. Hark says they’ve been in communication with BASF officials regarding the chemical compound. Hark says they are working against the clock with rain due in the area to get the truck away from ground that may become soft due to rainfall. 168 is expected to be closed in that area for several hours. For up to the minute road closings, go to modot.org