Oil waste eating away plumbing in contaminated Carousel tract neighborhood, study says

Years of state-led environmental investigations into massive oil contamination at Carson’s Carousel tract neighborhood missed a key problem for residents living amid the mess: the sewer pipes under some homes are literally corroded into dust.

Beyond the high cost of replacing sewer lines, the oil-degraded pipelines could present yet another major health concern for residents across the 50-acre community, a new city-commissioned study has found.

“The leaking, degraded, broken sewer pipes can no longer protect the occupants of the home from direct exposure to sewer gases,” the report states. “Sewer gases like hydrogen sulfide, for example, are extremely harmful to human health at certain levels. The potentially dangerous and harmful conditions … need to be addressed presently.”

The issue was discovered last year after several residents questioned whether they had stumbled on yet another pollution-related concern when their kitchen sinks backed up.

Plumbers, unable to do anything to clear the lines, put cameras down the pipes and saw complete carnage.

“There was no bottom of the pipe at all,” said one plumber, Andrew Velasquez of Rooter-Man. “It was unbelievable.”

LIVING AMID MASSIVE OIL POLLUTION

This issue with sewer pipes is the latest development in a decade-long saga for Carousel tract residents.

Developers of the 285-home community, which borders Wilmington, secretly buried remains of a former Shell Oil tank farm a few feet beneath the homes in the 1960s.

The burial was kept secret until routine testing discovered soil pollution in 2008.

Then, the state’s Los Angeles Regional Water Quality Control Board began investigating the extent of the problem and its threat to the health of thousands of residents exposed for decades to higher levels of benzene and other chemicals.

Despite five years of subsequent, extensive testing that included moving residents out of their homes for days to sample for contaminated air vapors, the agency failed to discover the plumbing issue.

However, the issue was moot by the time residents figured out what was happening. The water board’s investigation had already closed, and the residents had settled lawsuits for damages against Shell Oil and the developer’s owner, Dole Food Co.

CITY OPENED NEW INVESTIGATION

The new study, commissioned by city officials last year, removed and tested pieces of underground sewer pipes from underneath six homes.

Preliminary investigation results were made public for the first time last week, and the City Council is set to discuss the issue at its Tuesday meeting.

The report confirms just what residents and plumbers thought — the cast-iron sewer pipes are being eaten away as a result of sitting in wet, petroleum-soaked soil.

“Hydrocarbon-impacted soil has, in fact, caused, or has at least contributed to the cause of, premature degradation of cast-iron sewer pipes,” states the report, by HG Cornerstone. “The soil within the Carousel Tract is very tight and exhibits very poor drainage. Also, the concrete foundations for the former crude oil storage tanks left below grade act as a soil-water drainage barrier.”

The cast-iron pipes, it states, should last 100 to 150 years. But, at about 50 years old, some are corroded beyond repair.

Some residents are having their plumbing systems rebuilt at their own expense. Others can’t afford the expense of tens of thousands of dollars. It’s not clear if they will be reimbursed for the work, though water board officials have said they’re paying close attention to the city’s investigation.

Shell Oil officials said they are still reviewing the city’s report.

“The condition of the soil exposed during our pipe sample excavation and removal work varied from un-noticeably impacted by petroleum hydrocarbons to obviously impacted by petroleum hydrocarbons (staining and odors observed),” the report states.

Tests found that pipes surrounded by moisture and hydrocarbons in the soil were covered with bacteria that can “produce waste products that are able to cause corrosion of cast iron.”

LENGTHY SOIL CLEANUP

Since a massive, roughly $150 million community cleanup began in May 2016, workers have replaced oil-soaked soil in unpaved areas — mostly yards — around a few dozen homes. The water board decided that soil directly beneath homes could be left as-is.

Residents whose properties are being cleaned are moved into hotels, but their neighbors are forced to contend with heavy-duty trucks and strange odors.

Altogether, there are 24 clusters of homes to be partially cleaned, with each cluster containing eight to 10 residences. After a year, the project has just reached the fifth cluster — indicating that the cleanup will continue through 2022.

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