The County of Los Angeles could spend up to $143 million in costs related to this fall’s Dominguez Channel incident, a period of elevated hydrogen sulfide gas levels that began two months ago and has sickened thousands of residents in the surrounding area, including parts of Carson and Long Beach.

So far, the county’s Department of Public Works, the agency responsible for the Dominguez Channel, has spent $54 million on the Dominguez Channel odor from its Flood Control District Fund, Rossana D’Antonio, deputy director for development services and Emergency Management for the Los Angeles County Department of Public Works, said in an email.

The Public Works department’s budget for the fiscal year 2021-2022 is set at $3.6 billion, which includes the Flood Control District budget of $413 million.

Expenditures related to the Dominguez Channel incident include labor, equipment and materials, hotel accommodations, air purifiers, contracts, and claim reimbursements, D’Antonio said. Crews, for example, have been treating the water by spraying odor neutralizers and using aeration machines.

If the incident extends through March 2022, the cost for response and recovery might end up between $108 million to $143 million, according to Public Works’ latest estimate to the LA County Board of Supervisors on Nov. 30.

Public Works “will seek local, state, federal, or any other funding for any future costs or reimbursement of prior expenditures,” D’Antonio said.

Public Works will return to the Board with any funding requests and legal authorities for reimbursement. The department did not provide comments on how it intends to solicit the funding.

If an incident is declared an emergency by the state, for instance, the county could qualify for more funding.

The governor’s Office of Emergency Services spokesman Brian Ferguson said via email that since the incident first occurred, “the state has been coordinating closely with local government partner agencies to provide expertise and support to help address this issue.” The county remains the lead response agency managing this localized incident, he added.

Ferguson added that the state is still evaluating whether it might need to provide any support to the county.

The South Coast Air Quality Management District first received reports related to the foul-smelling hydrogen sulfide gas on Oct. 3 and then began working in conjunction with Public Works on Oct. 7. The pungent gas sickened thousands of people, leading the county to offer financial assistance including temporary relocation of local residents, largely from Carson, to hotels until Nov. 26.

Last week, the South Coast AQMD announced that it issued violation notices to the county and four companies following a probe into the noxious smell coming from decaying organic material in the Dominguez Channel. Similar to the claims made in recent lawsuits, the agency believes that chemicals sourced from local companies that washed into the Dominguez Channel, a flood control storm drain, caused the long-term stench.

How did the Dominguez Channel stench start? An interactive timeline