State Highway 29 reopened Thursday afternoon following an earlier hazardous materials incident near Zinfandel Lane in the St. Helena area. Five-gallon containers carrying some type of chemical were spilled on the roadway around 9 a.m. Thursday, according to the California Highway Patrol. The chemical was "smoldering" and authorities were not immediately able to identify the chemical because there were no labels on the containers, according to CHP reports. A Sig-alert was issued at 9:36 a.m. for the roadway as emergency personnel including Cal Fire established a perimeter around the hazardous material. The highway was closed in both directions from Stice Lane to Whitehall Lane, officials with the county of Napa said. There was another closure on northbound Highway 29 to Rutherford Crossing/state Highway 128.