Dozens of schoolchildren fall ill by cloud of tear gas in police training mishap

San Francisco Sheriff Paul Miyamoto speaks at his swearing in ceremomy at City Hall in San Francisco, Wednesday, Jan. 8, 2020. (AP Photo/Jeff Chiu)
San Francisco Sheriff Paul Miyamoto spoke with concerned San Bruno residents after a training exercise led to dozens of children being sickened. (Jeff Chiu / Associated Press)

Nearly 30 children and one adult became ill last week when a plume of tear gas used at a police training exercise drifted to a nearby elementary school in San Bruno, Calif., according to authorities.

In a report published Friday, the San Francisco Sheriff's Office said windy conditions and a lack of fog allowed for the cloud of tear gas to drift less than half a mile to Portola Elementary School on May 21.

"Usually, conditions are less windy and foggy, so the water droplets from the fog weigh down the [tear gas]," the report read, "which could explain why this exposure was an unprecedented event in the [department's] 20-year history of doing such training on site."

At the time of the incident, nearly 30 students at the school reported symptoms including coughing, watery eyes, wheezing and trouble breathing, said Matthew Duffy, superintendent of the San Bruno Park School District. There were also news reports of vomiting and rashes.

“More than a week later, we still have some students who are suffering adverse effects from the exposure to the tear gas and pepper spray in the air that day,” Duffy said. “It is now well-documented that some families needed to get emergency medical assistance to support their children who were suffering from the effects of the gas in the air.”

San Francisco Sheriff's Office said the crowd control training exercise on May 21 took place in an isolated area.

The Sheriff’s Office, which oversaw the crowd-control training exercise and launched an investigation into the incident, has since apologized to the students and their families as well as to faculty. Although the department informed the San Bruno police and fire departments of the training exercise, it said it plans to additionally send out alerts to residents in the future.

But Duffy said the district would be sending a "formal letter" to sheriff's officials requesting a halt to all "gas-related" training at the facility.

Parents became more distressed this week when the San Francisco Chronicle reported that some chemical canisters used during the training exercise dated as far back as the 1960s.

Tara Moriarty, spokeswoman for the Sheriff's Office, said a preliminary investigation into the incident revealed that the canisters that the UC Berkeley Police Department used for the training did not have expiration tabs.

“We believe, however, that these canisters had been pulled from storage," Moriarty said.

She did not say how long the canisters had been in storage.

She said it’s common for law enforcement agencies to use stored products for training exercises and that there “appears to be no greater health risk than using the same product that has been recently manufactured.”

But experts say there have been few studies that look into the long-term health and environmental effects of tear gas exposure.

Sven Jordt, an associate professor of anesthesiology and pharmacology and cancer biology at Duke University School of Medicine, said most research studies were conducted in the 1960s and '70s and excluded groups such as women, children and elderly people, including those with health conditions.

He said there have been a few studies in recent years, including ones conducted by the military, showing that long exposure to tear gas can have various deleterious health effects, including respiratory tract damage, reproductive health problems, and physical and psychological issues.

But Jordt said there are almost no research studies on expired tear gas canisters, and if there were, they would have been conducted by companies manufacturing the gas.

Jordt said one U.S. Army study looked at the toxic byproducts that form when the cartridges are burned and found some that were concerning.

"When these cartridges are expired, the expectation is that there are likely more of these byproducts formed," he said. "That's why there's an expiration date."

Jordt said the children vomiting is a sign of severe exposure to the tear gas.

"That usually doesn't happen to protesters," he said. "They must of been in quite significant distress."

The two-hour multi-agency training class for crowd control started at 12:45 p.m. and ended at a shipping container in an isolated area of the San Francisco County Jail in San Bruno, according to the department's report. At the time, winds were at 12 mph and climbing to 16 mph by 3:45 p.m.

During the training exercise, police officers deployed tear gas and pepper spray inside the structure.

San Francisco Sheriff's Office said the crowd control training exercise on May 21.
San Francisco Sheriff's Office said the crowd control training exercise on May 21 took place in an isolated area of the San Francisco County jail in San Bruno, less than half-a-mile from Portola Elementary School. The department plans to release findings of its investigation soon. (San Francisco Sheriff's Office v)

But the cloud of tear gas did not stay within the structure, instead drifting to the nearby elementary school.

Moriarty said after the incident that the Sheriff’s Office paused all future training exercises as it reviews its practices to make sure the community isn't endangered.

The Bay Area Air Quality Management District and San Mateo County Environmental Health Services said in separate statements that they were each investigating the incident.

"While there are no indications of any lingering environmental hazards at the site or in the surrounding area," the health department wrote, "the investigation will determine if all reporting requirements to the appropriate agencies were followed subsequent to the incident and whether appropriate contingency plans were in place to mitigate any release."

Since the incident , Duffy said, the school district has washed down the outside areas of the campus as a safety precaution. School officials also are continuing to gather information about the health of students and adults who were affected that day. The district also held a town hall meeting with Sheriff Paul Miyamoto to address community concerns.

“We will also be writing a formal letter to the S.F. Sheriff’s Department requesting the immediate end to all gas-related training at the facility,” Duffy said. “We appreciate the time the S.F. Sheriff’s Department has dedicated to understanding the events of that day, and we look forward to a partnership that sheds light on any inappropriate actions taken as well as needed steps to remedy the situation.”

Sign up for Essential California for news, features and recommendations from the L.A. Times and beyond in your inbox six days a week.

This story originally appeared in Los Angeles Times.