One lane of westbound Interstate 39-90 in Janesville reopened at about 2:30 p.m. Friday after a nearly 13-hour closure because of a chemical spill earlier in the day.More than a dozen people were evacuated from nearby homes as a precaution, officials said. All restrictions on the residents were lifted and both lanes on the interstate were reopened at 11:50 p.m. Friday, the Rock County Sheriff’s Office said. The Janesville Fire Department and the Madison Fire Department hazmat team responded to the spill, which happened after a crash involving two semi-trucks just before 2 a.m. Friday near mile marker 173.