Hundreds of people across several blocks felt tear-gas effects; air quality measurably degraded

In the thick of the Friday, Jan. 30, dinner rush at Marché, cooks and servers felt their eyes burn.

“The air was getting a little prickly,” said Jessica Blaine, the downtown restaurant’s CEO, who got an unsettling message from managers that night. “There was something in the air, both literally and figuratively.”

Across the street at the Eugene Federal Building, U.S. Customs and Border Protection officers threw tear gas canisters and smoke grenades at protesters — and a chemical fog rolled across the plaza and over about 10 surrounding blocks. 

“Our crew [was] coughing, feeling uncomfortable, so we made the decision to close a little bit early,” Blaine said. 

They were among at least 200 patrons and workers unknowingly exposed during the unrest, based on Lookout Eugene-Springfield’s estimates, calculated by calling hotels, restaurants and theaters within the plume’s radius. People walking and driving along Sixth and Seventh avenues, busy downtown routes, were also exposed. 

After declaring a riot at the federal building, the Eugene Police Department warned some 300 protesters that chemicals would be used if they did not leave. Some people dispersed before deployment, but still inhaled chemicals that spread beyond the federal building plaza.

The release of chemical irritants happened before, on Tuesday, Jan. 27, and it happened again Saturday, Jan. 31. 

Air quality declined all three evenings after federal officers deployed tear gas, according to readings from a sensor operated by the Lane Regional Air Protection Agency near Eighth Avenue and Lincoln Street.

The sensor detected the change because tear gas is released as an aerosol — a mist of tiny solid and liquid particles. Such particulate matter, or particulate pollution, is small enough to be inhaled deep into the lungs, is regulated for public health, and is measurable on sensors like that one, less than half a mile away from the federal building. 

The Air Quality Index, known as AQI, measures pollution, including particulate matter. A sensor operated by the Lane Regional Air Protection Agency detected the following over the last week:

• Tuesday, Jan. 27: The index spikes to 121, considered an unhealthy level at 4 p.m. before returning to moderate Jan. 28 at 3 a.m. and then good at 11 a.m.
• Friday, Jan. 30: The index rose from 46, considered good, to 51, considered moderate, around 7 p.m., before returning to the good range about an hour later.
• Saturday, Jan. 31: The index showed a longer increase, measuring 44, considered good, at 7 p.m., rising to 53, considered moderate, at 8 p.m., and peaking at 58 around 11 p.m. before returning to the good range by 2 a.m.

An overnight inversion — when cold, dense air becomes trapped in the southern Willamette Valley — slowed the clearing of chemicals near ground level in downtown Eugene over the weekend, said Matt Sorensen, a spokesperson for the agency. 

He said the sensor measures overall pollution and cannot isolate a single source.

“While we can’t attribute the AQI change exclusively to tear gas, it could have played a role,” Sorensen said. “It’s unfortunate that downtown Eugene residents had to endure lingering tear gas effects this weekend.” 

There is no level of particulate matter considered completely safe to breathe, and research links exposure to cardiovascular and respiratory disease, according to the Environmental Protection Agency and the American Lung Association.

Effects of tear gas could extend beyond the weekend, especially for people with asthma or chronic lung diseases, national researchers and local medical professionals said. 

‘Sitting and sticking’ 

Sven Eric Jordt, a Duke University anesthesiology professor whose lab studies chemical irritants and human response, describes the residue left by tear gas as contamination because it sticks to people’s skin and clothes and settles on buildings and furniture if it gets indoors.

“The tear gas agent is actually not a gas,” he said. “It doesn’t dissipate. It’s not like air or some other gas that’s just blown away. It’s just sitting and sticking there.”

Jordt reviewed videos and photos from Friday’s unrest with Lookout Eugene-Springfield and identified the devices used and the chemicals they released. 

• CS (chlorobenzylidenemalononitrile): A yellow solid chemical, often in powder form, that is dispersed from canisters or grenades as fine particles in a mist, vapor or liquid spray.
• Pepper agent (OC or oleoresin capsicum): A yellow or white solid derived from chili peppers that is dispersed in a similar way, using aerosols from canisters or grenades.
• Smoke grenades: Devices designed to emit smoke that can be used alone or combined with irritant chemicals. They contain a chemical fuel that burns to spread the smoke and can release other harmful chemicals, including heavy metals such as chromium and lead, into the air.

These chemicals activate tiny pain-sensing nerves, causing intense pain that makes people’s eyes water and shut tightly. 

“That’s why they are called tear gas,” Jordt said. 

And for many, the experience feels similar to drowning — an experience that can have consequences in the long run, according to Rohini Haar, an assistant professor of epidemiology at the University of California, Berkeley, who has authored one of the most comprehensive reports on crowd control and health. 

Research in the field is developing as more evidence emerges, Haar said. As an example, she pointed to a survey conducted by the Kaiser Permanente Northwest Center for Health Research that surveyed people in Portland who were exposed to tear gas at various demonstrations and protests over a month in 2020. 

Nearly all respondents reported physical symptoms, and many also reported mental health effects in the days following exposure. They reported headaches, cramping, diarrhea, exhaustion, and a delay in menstrual cycles. 

But learning more about these chemicals is challenging. 

“To me, the big unanswered questions are in the process that it takes for these weapons to come onto the market,” she said. “The other thing is for things like chemical irritants: a better understanding of what exactly is in the canister, the quantity, the concentration and what else is in there.” 

The Department of Homeland Security did not respond to questions from Lookout Eugene-Springfield about considerations of health risks. The Eugene Police Department, reiterating that it did not deploy any tear gas, also did not answer the question. 

Tuesday, Feb. 3, a U.S. district judge issued a 14-day temporary order restricting the federal use of tear gas, rubber bullets and other munitions at Portland’s U.S. Immigration and Customs Enforcement Building. It does not apply to Eugene’s federal building.

Excessive force and public health 

During a news conference Sunday, Mayor Kaarin Knudson called the tear gas — also shot at people with pepper pellets — part of “excessive use of force against community members who are not breaking any laws.” 

Knudson framed her concerns around broader public safety, particularly for people demonstrating on the steps of the federal building. 

“I am working with our state partners and our national partners to address how it is that we can protect our local community members from excessive uses of force when people are exercising their constitutional rights,” she said.

With no Eugene police, fire or other city resources consistently stationed near protests, volunteer medics have organized to remain on the edges of demonstrations. One of them, a registered nurse who goes by Crow, described the role as that of a lifeguard, watching for signs that someone is in trouble. 

Lookout Eugene-Springfield is not publishing Crow’s last name because he said he fears harassment toward his family for speaking publicly, citing similar treatment faced by other registered nurses who spoke out after the death of Alex Pretti, a 37-year-old Department of Veterans Affairs hospital nurse who was shot and killed by federal agents during a protest. 

“If ICE is keeping people away from folks who’ve been injured, our ability to help people is really limited,” Crow said. 

Crow attended Eugene’s vigil last week organized by the Oregon Nurses Association, at the federal building. Before leaving, he passed along dozens of plastic bags to other volunteer medics — filled with decontamination wipes soaked in a solution he made using water, sugar, citric acid and baby shampoo.

Fellow volunteers handed out the wipes Tuesday night after tear gas was deployed following the vigil, advising people to blot exposed skin first, stay calm and avoid reexposure.

That guidance mirrors advice shared by Patrick Luedtke, Lane County’s senior public health officer. 

We worry about everyone. Patrick Luedtke, Lane County’s senior public health officer. 

“Go home, take a shower, wash yourself, take those clothes off that have been exposed. And, typically, the recommendation is to throw them away,” Luedtke said.  

Unlike other forms of air pollution, like wildfire smoke, tear gas is generally short-lived, which gives Luedtke some relief. But the same people sensitive to smoke are often sensitive to tear gas. 

“People with really brittle asthma that’s not well controlled,” he said. “Or emphysema. They could be tripped into an asthma attack that could last for days, even a week or two before it is resolved.”

“We worry about everyone, but those are the highest-risk people,” he said. 

That concern also extends to children, whose bodies are still developing. On Friday, tear gas entered the Hult Center for the Performing Arts through its HVAC system during a showing of “Harry Potter.” About 50 people were affected, mostly in the lobby, according to organizers. 

HVAC systems were also how the chemicals entered Marché, where the kitchen ventilation pulls outdoor air inside to replace air that commercial cooking hoods exhaust, Blaine told Lookout Eugene-Springfield. 

She and the restaurant are considering developing a contingency plan for future protests involving chemical exposure or nearby unrest. 

“We want to be sure that everybody can get home safely and be here safely,” she said. “It’s a balancing act every night, but especially so when there’s violence going on.”

Micheal Zhang contributed to this report.