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Climate and Environment

What We Know So Far About How And Why A Pipe Spilled 8.5 Million Gallons Of Sewage In Carson

A construction crane, black van, and water tanker truck sit in the middle of a construction zone covered in hoses along a freeway in the daylight as several workers wearing bright yellow and orange vets walk around.
The site of the spill in Carson.
(Courtesy Los Angeles County Sanitation Districts)
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The sewer line that broke in Carson last week and spilled 8.5 million gallons of untreated sewage was over 60-years-old.

The line’s age should have triggered red flags sooner, according to L.A. County Supervisor Janice Hahn.

“We need to understand how this aging infrastructure wasn't replaced sooner,” Hahn said. “And then how is all of the … infrastructure of the LA County Sanitation …district holding up? Are there more pipes that are scheduled to be replaced? Should we, you know, really pick up the pace as we're replacing aging infrastructure?”

The spill was the largest recorded in the history of the L.A. County Sanitation Districts, according to spokesperson Bryan Langpap.

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Two sanitation workers stand in a dirt pit next to a pipe and pink retaining wall. One worker sprays a stream of water deeper into the pit.
Two LACSD workers on the site of the Carson spill.
(Courtesy Los Angeles County Sanitation Districts. )

“We've been tracking the quantity of our spills since 1981,” he said. “And that is the largest spill we've had by far. [The previous largest spill] was one-and-a-half million gallons.”

The previous record-breaking spill took place in 2006 in Manhattan Beach after multiple failures at a pumping plant, Langpap said.

LACSD services about 5 million people in L.A. County. Larger spills have been recorded in greater L.A., like the 17-million gallon spill from the Hyperion Plant in El Segundo. But that plant falls under the jurisdiction of Los Angeles City Sanitation, not LACSD.

The Timeline

The spill was first discovered on Dec. 30 around 5 p.m. and halted by 9 p.m. on New Year’s Eve. Initial estimates pegged the volume of the spill between 6 and 7 million gallons.

According to the County Department of Public Health, up to 4 million gallons of untreated sewage made its way into the ocean via the Dominguez Channel, which terminates in the L.A. Harbor. On December 30, Public Health closed beaches from Rancho Palos Verdes to Long Beach.

Seven beaches were originally forced to close due to the spill, but five of the locations had reopened by Monday, according to an update issued by LACSD. Cabrillo and Long Beach remained closed at the time of this publication.

Check Out Current Conditions

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The cause of the sewer system’s failure has not yet been determined, according to Langap.

“We still need to do more investigation to figure out exactly what caused the pipe to collapse,” Langap said. “It's likely that the rain had an impact but how the dominoes exactly fell is something we still need to investigate further.”

Supervisor Hahn is penning a letter to LACSD to demand a deeper dive into the incident.

“We need to get to the bottom of this, we need to understand what happened…and more importantly, County Sanitation needs to understand that a spill of this magnitude is completely unacceptable and dangerous,” Hahn said. “And we have to make sure that it never happens again.”

Download and read the full letter below.

What's Been Done So Far

Currently, a series of bypasses have re-routed the spill from the broken line. But a more permanent solution is on its way and is expected to be ready for implementation by Jan. 10.

"So we are planning to repair the sewer via a process called slip-lining, where we would take a 42-inch pipe and shove it inside the existing 48-inch pipe,” Langpap said. “So now you essentially have a pipe within a pipe and the flow would be carried in this brand new pipe that's corrosion-resistant and has its full strength.”

The materials needed to install the pipe were ordered last week and are expected to ship from Texas by the end of this week. Arrival is slated for Jan. 10 and construction is expected to get underway immediately after the delivery.

LACSD's Monday update outlined a repair time of 4-5 days once all materials are on hand. After the slip-ling is installed and the area is restored, the nearby 110 off-ramp will be re-opened to traffic.

The spill, which remained active for around 28 hours, could have been nipped in the bud much quicker if it happened somewhere between June and December, said Langpap.

“So about 200 feet east of where the collapse occurred on Figueroa Street, we have a new sewer that's under construction,” said Langpap. “Unfortunately, we got six to 12 months left. If, if this had been, you know, six to 12 months later, we probably would have diverted nearly all of the flow to the new sewer and this issue wouldn't have happened.”

After the spill itself stopped, LACSD crews continued to clean up through Saturday. On Monday, a 3rd-party cleaning crew was back working to address any lingering filth.

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