Politics

Police decked out in gas masks and armed with less than lethal munitions move through a cloud of gas.

Tear gas and other chemical weapons used on crowds could cause health problems to both agents and protestors. Sean Bascom/Anadolu via Getty Get your news from a source that’s not owned and controlled by oligarchs. Sign up for the free Mother Jones Daily.

On January 31, federal agents fired tear gas into a crowd of civilians, clergy, and children gathered outside the ICE building in Portland, Oregon. Witnesses say, and video shows, that the demonstration was largely peaceful before the gas was deployed. In the weeks since, a federal judge moved to restrict the use of these chemical munitions at the site following reports that agents used them against demonstrators who posed no imminent threat.

Under the second Trump administration, displays of force against protesters have become increasingly common. So it’s important to know which chemicals are being deployed against those exercising their First Amendment rights—because they’re not benign.

Tear gas, the most widely deployed crowd-control weapon, can cause more harm than temporary irritation. Beyond burning eyes and skin, it has been linked to corneal ulcers and menstrual cycle disruptions, with some reports suggesting possible associations with miscarriage.

But tear gas is just one type of chemical used by federal agents for crowd control.

On January 24, federal agents used hexachloroethane smoke—more commonly known as HC—on protesters at the same Portland ICE facility where they would tear gas children just a week later. According to medical experts, HC is “demonstrably more dangerous” than tear gas. The smoke releases zinc chloride, which can cause chemical burns, acute respiratory distress, and pulmonary edema at high concentrations. Safety data from the manufacturer also warns of potential long-term risks, including organ damage and cancer with repeated exposure.

The US Army has been moving away from HC use in training for decades due to health risks to soldiers, replacing it with less toxic alternatives. Yet spent HC canisters have been documented at protests in Portland—including during the 2020 Black Lives Matter demonstrations. Past reports linked exposure to symptoms ranging from vomiting and hair loss to prolonged appetite loss and significant weight decline.