Federal agents aggressively deployed powerful chemical irritants during Operation Metro Surge, a recent report found, in many cases at close range on protesters. Dr. Asha Hassan is a professor at the University of Minnesota Medical School who has studied the use of tear gas by law enforcement. Mild symptoms of tear gas exposure include irritation of the eyes and lungs. If they are using these chemical irritants that people are inhaling and consuming, then they have to justify that this is safe.” Tear gas is deployed after protesters clash with federal agents in north Minneapolis on Jan. 14, 2026.