Living among Southern California’s industrial facilities can have adverse effects on residents’ health and quality of life.

Rendering plants produce odors that are among the most offensive. These facilities receive dead animals, as well as kitchen grease and wastewater, and turn those materials into ingredients for pet food, cosmetics, and other products. Odors from the plants sometimes seep into neighboring communities and can cause health problems.

Four rendering companies are clustered together a few miles southeast of downtown L.A., in and very near the city of Vernon, along with a handful of slaughterhouses, meat processors, and many other industrial facilities. Public health experts interviewed by LAist say the density of these facilities, coupled with the hazardous chemicals rendering plants can emit, pose serious health risks to nearby residents.

But SoCal residents don’t have to face these issues alone. If you encounter a foul odor in your neighborhood, you can reach out to the South Coast Air Quality Management District (AQMD).

This agency is tasked with monitoring air quality in the area. In 2021, it received nearly 400 complaints about rendering plants in the region — and many more in the years before that, according to Wayne Nastri, the regulatory agency’s executive director. The number of complaints dropped significantly this year, but the issue still persists.

An LAist review of AQMD records found that these odor complaints have been lodged from homes and businesses in surrounding neighborhoods, as well as from local schools. One person who reported air problems said they’ve been waking up to the stench of “burning animal carcass” for the past 32 years.

Where else have odor issues emerged?

Since 2000, most air quality complaints to AQMD have involved odors. Agency officials say the spike in 2021 was in response to problems at Dominguez Channel and the Hyperion Water Reclamation Plant.

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Courtesy AQMD

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Back in 2021, South Bay residents endured the smell of rotten egg for several days. The stench was later attributed to a large warehouse fire that caused chemicals in beauty products to seep into the Dominguez Channel. Those chemicals killed off vegetation along the channel, releasing high levels of hydrogen sulfide, a colorless gas that can be harmful to human health. Residents reported headaches, fatigue, and respiratory problems.

That same year, the Hyperion Water Reclamation Plant in Playa del Rey discharged 17 million gallons of raw sewage into the Pacific Ocean. Community members experienced nausea, headaches, and eye irritation. To ward off the smell, they shut their windows and avoided going outdoors. Some of them wore masks inside their homes.

What is the South Coast Air Quality Management District, and what does it do?

AQMD — sometimes also referenced as SCAQMD — is a regulatory agency that manages air quality in Los Angeles, Orange, Riverside, and San Bernardino counties. The agency’s employees work to control emissions from stationary sources of air pollution, including power plants, refineries and gas stations. AQMD issues permits and inspects these businesses to evaluate their compliance with local air quality rules, which are aligned with federal and state standards.

Emissions from mobile sources, like cars, trains, and airplanes, are monitored by other agencies.

If you live in northern L.A. County, there’s one exception to keep in mind: The Antelope Valley — which includes cities like Lancaster and Palmdale — is outside AQMD’s jurisdiction. That area is monitored by the Antelope Valley Air Quality Management District.

Why is air quality important?

Jill Johnston, associate professor of population and public health sciences at USC, underscores that strong odors don’t just diminish local residents’ quality of life, they can also impact their health.

Emissions from rendering plants can contain hydrogen sulfide and sulfur dioxide, she said. These chemicals can exacerbate asthma symptoms and elevate blood pressure, Johnston added, and long-term exposure can adversely affect respiratory and cardiovascular systems.

On its website, AQMD warns that air pollution can “cause or worsen many health problems, including asthma attacks, respiratory disease, heart disease, certain types of cancers, and premature death.”

How can I report a foul odor?

For residents who live within AQMD’s boundaries, there are three ways to file an odor report:

• Call 1-800-CUT-SMOG (1-800-288-7664) 
• Visit AQMD’s online complaint system
• Download and use AQMD’s phone app

All options are available 24 hours a day. During business hours (7 a.m. – 5:30 p.m. Tuesday through Friday), your call will be answered by an attendant. Outside of business hours, you’ll be asked to leave a voice message.

The app is especially useful because it enables you to track the status of your complaint. You can also attach any images related to the issue.

How to report an odor complaint via the AQMD's app. Click for more information.

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Courtesy AQMD

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How to complete the complaint form via the app. Click for more info.

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Courtesy AQMD

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In addition to odor complaints, these options can be used to report excessive dust or smoke in your neighborhood.

If you live in the Antelope Valley, you can file a complaint by completing a form on this website or by calling 661-723-8070. You can also email the agency at complaints@avaqmd.ca.gov.

What information should I have at hand?

If you encounter a strong odor, think of specific ways to describe it (like “rotten eggs,” “burned plastic,” etc.) and try to identify its source, said Victor Yip, who oversees compliance and enforcement at AQMD.

Air quality agencies will ask you for the following information:

• The time the air quality incident occurred and whether it’s continuing at the time of your report
• The type of air quality complaint (dust, odor, smoke, etc.)
• Whether you have experienced this type problem in the past
• The wind direction, if known
• The name and address of the alleged source and the type of facility, if known
• Your contact information

When it comes to recurring odor issues, it’s useful to tell the agency the full scope of the problem, for example, "This happens every night at this time," Yip said. These details help inspectors “track [the odor] and get more information to be able to launch our investigation.”

Yip urges residents to file complaints when an odor issue is happening, instead of waiting for it to pass, which can make it difficult to confirm and investigate.

He also noted that AQMD takes anonymous complaints. However, if you choose not to provide your contact information, the inspector won’t be able to contact you to learn more about the issue or provide any follow-up information.

What happens if the smell is occurring outside of business hours?

When the agency receives complaints after hours, they’re routed to a standby supervisor who reviews them to determine if it’s necessary to take immediate action. Unless the air quality incident appears to pose a serious threat to the health or safety of the public, the supervisor usually dispatches an inspector to follow-up the next business day, Yip said.

If AQMD receives three or more complaints from different households about the same issue, an inspector will be dispatched after hours.

How are air quality complaints resolved?

Some complaints can be resolved over the phone without additional follow-up. For example, after getting a call back from an inspector, a community member might say the odor they encountered is no longer present.

Other odor complaints require more work. If the source of a stench is unknown, an inspector will investigate potential sources based on the description in the complaint.

In these cases, the inspector assigned to your complaint might call for additional information. Yip said investigations are sometimes delayed when community members don’t answer follow-up calls.

“We understand everyone's busy,” he added, “but it would be just very, very helpful to our inspectors if you can pick up the phone.”

Following that chat, the inspector will locate and attempt to verify the source. Then, the inspector will survey the facility to determine the cause of the air quality problem.

When there are serious violations, penalties for the offending business can go up to $10,000 per day.