The Fond du Lac County Sheriff’s Office is investigating a semi crash on Interstate 41 in Fond du Lac. The crash happened shortly after 7am Tuesday on 41 at the Highway 151 off-ramp. A preliminary investigation found that a southbound semi had attempted to exit interstate 41 at Hwy 151 and lost control on the wet pavement. The semi jack-knifed and overturned in the eastbound ditch of interstate 41. A 150 gallon fuel tank was ruptured and spilled into the ditch.