Low levels of hydrogen sulfide found in air near Dominguez Channel

Air monitoring has revealed “very low levels of hydrogen sulfide” from a foul odor that has been reported for days near the Dominguez Channel in the Carson and West Long Beach area, Los Angeles County health officials announced.

The odor came from an organic material drying out after being left on the channel banks during low tide, a statement issued Saturday said.

Public Health officials conducted air monitoring over the last two days and found very low levels of hydrogen sulfide in the air (.4-.9 ppm) east of the Dominguez Channel, the county said. At these low levels, hydrogen sulfide does not have long-term health effects, but does cause “nuisance odors that may cause short-term symptoms and impact quality of life,” the statement said.   

Carson Mayor Lula Davis-Holmes said Friday investigators believed the odor may have been caused by a leaking pipeline, and she called for a full investigation.

Nevertheless, the statement noted that some residents may experience temporary symptoms such as headaches, nausea or irritation to the eyes nose and throat, which should go away when the odors are no longer present.

Residents experiencing persistent symptoms were urged to contact health care providers, especially if they have chronic health conditions.   

“Local officials are continuing to work to identify the source of the odor, however, until the odor event subsides, Public Health recommends preventing outdoor odors from entering the home by keeping doors and windows closed as much as possible while odors are present,” the statement said.

Officials recommended using an air conditioner or portable indoor air filter such as a High-Efficiency Particulate Air (HEPA) filter.  

Residents in the Carson area had reported the foul odor for several days, according to a statement from the city of Carson on Thursday night.  

A team from the South Coast Air Management District investigated whether any area refineries or waste facilities were the source of the odor but “identified no facility releases into the Dominguez Channel that would account for any harmful health concerns,” the city statement said.

At about 10:15 a.m. Friday a hazardous materials team was sent to the area of the northbound 405 Freeway near Avalon Boulevard, according to the Los Angeles County Fire Department.  

Hazmat personnel determined there was no hazard to the public or threat to life, but were not able to determine the source of the odor, and they turned that investigation over to the South Coast Air Quality Management District, the fire department reported. No injuries were reported.  

The city of Carson urged residents or anyone affected by the odor to notify the South Coast AQMD by calling 800-CUT-SMOG (288-7664).

UPDATE: Carson mayor now says foul odor due to leaking pipeline, calls for investigation

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