After more than two weeks of inhaling toxic fumes that can cause headaches and nausea, Carson residents are now advised to avoid prolonged outdoor exercise at night and in the early morning.
The amount of hydrogen sulfide emanating from decaying vegetation and marine life in Dominguez Strait has exceeded state-set thresholds in some locations but is not considered “imminently dangerous,” Los Angeles County health officials said Tuesday.
However, they advised people to avoid prolonged outdoor activities between 9:00 pm and 8:00 am and in cases where the smell, which has been compared to rotten eggs, vomiting and farting, becomes particularly strong.
Businesses with a strong odor should turn on the air conditioners for several hours before workers appear, they said.
“These levels may cause marked discomfort, irritation, or certain asymptomatic non-sensory effects,” Los Angeles County public health officials said in a press release. “However, these effects are not expected to result in shutdown, but they are expected to be temporary and reversible as exposure decreases or ceases.”
Officials have previously recommended that people close doors and windows – even if many do not have air conditioning – and move temporarily if the smell makes them sick.
County officials announced last week that residents could be reimbursed for air purifiers and hotels. However, it may take several weeks for a refund to be received.
The City of Carson has also established a cost recovery program.
Air quality monitoring stations have been installed in various locations near the canal, with monitoring efforts concentrated in schools and centers for the elderly, district health authorities said on Tuesday.
Hydrogen sulfide levels were particularly high in the late evenings and early morning in areas near the canal, prompting warnings about exercise during these hours.
After the stench was first reported to the South Coast Air Quality Management District on Oct. 3, it took county teams 12 days to begin treating the flood control channel to reduce the odor.
On Friday, workers began spraying the flood control canal with a biodegradable odor neutralizer called Epoleon, which converts hydrogen sulfide to salt.
The odor is expected to disappear within five days of treatment – or in the middle of this week, officials said.
On Tuesday, workers installed equipment that pumps millions of tiny oxygen bubbles into the water to prevent additional build-up of hydrogen sulfide.
Carson City Council announced last week that the smell was uncomfortable.
But Rep. Nanette Barragán (Democrat from San Pedro) criticized the city and county’s efforts as too slow and insufficient to meet the needs of low-income residents who cannot afford to wait for reimbursements.
On Monday, she asked Governor Gavin Newsom to declare a state of emergency.
“These residents are in need of direct assistance, so I am asking you to declare a state of emergency so that residents can receive direct assistance and not be in debt because of this event,” she wrote in a letter to Newsom.
In a typical year, storm water would wash away more of the underwater vegetation that is now decaying. The drought has triggered additional population growth this year, officials said.
Vegetation was decaying beneath the surface, according to the county’s Department of Public Works – a process that may have been speeded up by dumping pallets and cardboard upstream that fed the bacteria.
County agencies are investigating whether the fire in the pallet warehouse led to a landfill.