Residents burdened by the foul-smelling Dominguez Channel will likely have to endure its impacts for another week as the county continues to treat the channel’s water, a county official said Tuesday night.

Since Friday, crews have been spraying a water treatment product called Epoleon, which is non-toxic and biodegradable, into the channel. Los Angeles County Department of Public Works Director Mark Pestrella said during a Carson Council meeting on Tuesday that the product has helped reduce levels of hydrogen sulfide, which is the source of the pungent, rotten-egg smell, but has not yet eliminated the odor.

Additionally, Pestrella said his team has installed 12 aeration devices, which will be used over a three-month period to inject tiny bubbles into the water. The devices will help introduce oxygen into the water, which will help stop the production of hydrogen sulfide.

“Based on this application and early results, we expect the public to begin to notice a significant change in the air quality throughout this week, hoping we really come to completely not having the event by the weekend,” Pestrella said.

Public health and air quality updates

In the meantime, the county Department of Public Health announced Tuesday afternoon that it is now advising Carson and surrounding communities to avoid “prolonged outdoor activities” between the hours of 9 p.m. and 8 a.m. near “the vicinity” of Dominguez Channel.

Residents have repeatedly said that the odor worsens during the evening hours, which keeps them up at night or wakes them in their sleep.

Levels of hydrogen sulfide can fluctuate based on weather patterns, wind and time of day, according to the county’s public health department.

“The levels appear to have been higher with low wind, at low tide, and with lack of light, but these theories are still being evaluated,” according to a statement from the public health department.

A fixed air monitor was set up last week at the intersection of 213th Street and Chico Street, near a residential neighborhood adjacent to the channel, which has shown high levels of hydrogen sulfide in overnight readings obtained from Thursday, Oct. 14 through Saturday, Oct. 16, the county said.

“The highest 1-hour average concentrations over those three days were 3.7 ppm (parts per million), 6.2 ppm, and just under 7.0 ppm, respectively,” the county said.

Hydrogen sulfide is immediately dangerous to life and health at or above 100 ppm, according to the county.

The Dominguez Channel near the 405 Freeway exit on South Avalon Boulevard and East Dominguez Street on Thursday, Oct. 14, 2021. Photo by Crystal Niebla.

As of Tuesday, the county said that the source continues to be considered as naturally decaying organic material, such as vegetation and marine life, at the bottom and sides of the channel in Carson.

However, Pestrella said that his department and other local government agencies are investigating a discharge of materials, including cardboard, pallet pieces and ethanol that may or may not have entered the channel intentionally. Last week he said the foreign materials that entered the water, which might have originated from a nearby pallet fire, could have exacerbated the naturally occurring decay within the channel, but that theory is still under investigation.

No other sources for hydrogen sulfide have been identified at this time, the county said in a statement.

South Coast Air Quality Management District, county Fire Hazardous Materials and the Department of Public Health will continue to evaluate and monitor hydrogen sulfide concentrations and mitigate health impacts.

Pestrella said that the county has partnered with Carson to provide air purifiers at distribution sites, vouchers for relocations and a community outreach vehicle at the Carson Community Center. Residents can visit the county website or call 211 for help with air purifier reimbursements or relocation assistance.

Criticism over solving the odor problem

On Oct. 14, Pestrella estimated that after treating the water, the foul odor would have improved within three to five days. But the odor continues to permeate the air, and residents are still coping with it.

“We’re on day five,” Carson resident and community organizer Ana Meni, 42, said on Tuesday. “It still smells.”

The stench is most concentrated in Carson near the South Avalon Boulevard exit of the 405 Freeway. Communities of Wilmington, Gardena, Torrance, Redondo Beach and parts of Long Beach have also been impacted for more than two weeks now.

Meni, who lives half a mile away from the channel, recently relocated to a Holiday Inn in Long Beach.

She joined a rally on Tuesday outside of Imperial Avalon Mobile Estates, a community for older adults that’s located near the Dominguez Channel.

Meni said that she and other residents want faster remediation of the pungent smell, which has caused a variety of symptoms for residents from headaches to eye irritating to vomiting. As the public continues to wait for its local government to fix the problem, the distrust from residents continues to grow.

A small group of Carson residents rallied in protest against the Dominguez Channel odor near the Imperial Avalon Mobile Estates in Carson on Tuesday, Oct. 19, 2021. Photo courtesy of Ana Meni.

Even Carson council members are becoming skeptical of the county’s remediation timetable. During the City Council meeting Tuesday night, members said they will consider contracting a third party to investigate the cause of the Dominguez Channel odor as the smell persists.

City Manager Sharon Landers said the county told her they had a very limited supply of Epoleon when they first began spraying the water on Friday and got the rest of the supply on Tuesday to continue the water treatment.

“This is so unacceptable on so many levels,” Councilman Jawane Hilton said.

The council expressed frustration over the changes in the county’s theories for the source of the odor and misestimations of the remediation timeline.

“I’m tired of the misinformation and the innuendos,” Councilman Cedric L. Hicks said. “You’re telling me one thing, and it turned out to be a lie.”

When asked if the city plans to sue the county, Carson Mayor Lula Davis-Holmes said after the meeting that, right now, Carson is in “information-gathering mode” to find solutions to the odor, help affected residents and make sure this doesn’t happen again.

“I’m not into lawsuits, I’m into remediation right now,” Davis-Holmes said.

By contrast, Meni said that residents are so upset with the odor incident that some have told her they might take legal action.

Many are angry that the problem still hasn’t been fixed. Residents falling sick from the air should be evacuated, she said.

“If you think that this is healthy enough, then why are all the (crew) workers in full hazmat gear?”

Congresswoman calls for state of emergency to be declared over Dominguez Channel odor