The Alpine Road on-ramp to Interstate 280 near Portola Valley was reopened at noon Monday after crews removed two mysterious containers that prompted a hazardous materials investigation, fire officials said.
Cal Fire Battalion Chief John Pearl said the scene was cleared around 11:30 a.m. and Caltrans reopened the on-ramp about half an hour later.
Pearl said a crew performing roadside cleanup found two plastic 55-gallon drums in the area of the Alpine Road on-ramp at about 8:20 a.m.
Cal Fire, Santa Clara County fire and the Woodside Fire Protection District were called to the scene to investigate what was inside the containers.
Pearl initially said it appeared the drums could contain some type of oil. He said there had been very little leakage, and none spilled into any waterways, he said.
Crews determined that the substance inside the drums was not toxic. Caltrans removed the drums from the roadway.