Police reported the incident at 12:56 p.m. They say a NorCal Portable Services sanitary truck was traveling in lane five of northbound 101, just south of the San Antonio off-ramp, when a black sedan cut off the truck to exit.
The truck then veered right, hit the barrier on the right shoulder, and lost control, CHP said.
After losing control the truck veered left across all lanes and hit a white sedan in lane one, then hit the center median wall and overturned, landing mostly on southbound lanes.
A small portion of the 1,000 gallons of human waste being transported spilled into the roadway.
At one point, three lanes on each side of the highway were closed to allow CalTrans crews to clean up the mess.
Southbound lanes opened around 3:30 p.m. and northbound lanes were back open by 5 p.m.
CHP says the driver of the black sedan has not been located. Officials are asking for witnesses to step forward with any information.
No injuries were reported, as of Wednesday evening.
#BREAKING: Sewage spill on NB 101 near San Antonio Rd on the Mountain View/Palo Alto border. Truck was carrying approx. 1,000 gallons of human waste. Small portion spilled onto the hwy, per CHP. CalTrans now working to empty the truck to get it upright. Massive traffic delays. https://t.co/Pp08mpCqXh— Chris Nguyen (@ChrisNguyenABC7) August 14, 2019
Traffic nightmare in the South Bay due to a sewage spill/ax on NB 101. Very slow going. Traffic is backed up southbound into Menlo Park and northbound into Mountain View. It’s going to take a long time for road conditions to recover from this. Take 280, if possible. #ABC7Now pic.twitter.com/NpeaEqdj2G— Chris Nguyen (@ChrisNguyenABC7) August 14, 2019
Avoid the area, unknown ETO and it might be very stinky in the area 💩 pic.twitter.com/LycOZrlUE5— CHP Redwood City (@CHP_RedwoodCity) August 14, 2019
Update: NB #3 lane open only #1 and #2 remain closed.— CHP Redwood City (@CHP_RedwoodCity) August 14, 2019
#1, 2 & 3 SB lanes remain closed. Avoid the area... pic.twitter.com/QHMqdRmM28
Preliminary: NorCal sanitary truck was traveling NB in # 5 lane jist south of San Antonio Offramp when a blk sedan in # 3 lane attempts to take the offramp and cuts off the truck. Truck veers right, hits attenuators on right shoulder and loses control.— CHP Redwood City (@CHP_RedwoodCity) August 14, 2019
Continued: After losing control, truck veers left across all lanes and strikes a white sedan traveling NB on the #1 lane, then hits center median wall and overturns landing mostly on SB lanes. It's a miracle no one on SB side was hit as well as there were no injuries reported. pic.twitter.com/aMQQ8gYJpd— CHP Redwood City (@CHP_RedwoodCity) August 14, 2019
We have blocked the #4 SB lane in order to allow the tow truck to maneuver and upright the truck. Only #5 lane open. If you don't have to be on US-101 SB avoid the area or you may be stuck in heavy traffic pic.twitter.com/qu0L4aMuJg— CHP Redwood City (@CHP_RedwoodCity) August 14, 2019