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.

Tear gas canisters themselves can be lethal if fired at protesters’ head, as they were in Iraq in October and November 2019. The other most common kinds of chemical weapons used on civilians are ...

Police used tear gas to disperse pro-Palestinian protesters at the University of Arizona Tucson campus after they refused to leave their encampment, according to numerous reports.

A release of tear gas and pepper spray during a training exercise at the San Francisco County Jail in San Bruno on Tuesday led to students at a nearby elementary school to become sick, officials said.