A Sig-alert has been issued this morning for a big rig truck that spilled an unknown liquid into lanes of eastbound Interstate Highway 580 near Five Canyons Parkway in Castro Valley.
Two right lanes are blocked on the highway as hazardous materials crews and California Highway Patrol officers investigate the spill.
Officers have not determined what the liquid is, but are re-routing traffic around lanes where the fluid spilled around 7:10 a.m.
As of 8 a.m., the big rig was off of the roadway and officers did not have reason to believe the spilled liquid was hazardous, according to Sgt. George Gori.
There is no estimate for when those lanes will reopen, according to the CHP.