The United States government, on March 22, 1965, officially declared that military forces deployed tear gas and herbicides as chemical weapons against Vietcong combatants during the Vietnam War. This revelation, a pivotal moment in the conflict, shocked the world and sparked grave ethical concerns, as Americans publicly admitted to using chemical weapons.

US forces employed tear gas to expel enemy fighters from underground hideouts and Agent Orange as jungle-clearing herbicides to eliminate Vietcong vegetation cover. Despite tear gas being classified as nonlethal, its use as a weapon of warfare had severe and long-lasting effects. The employment of herbicides caused not only severe environmental damage but also long-term health issues for both military personnel and Vietnamese residents. American forces believed jungle tactics needed chemical weapons for strategic military superiority during the Vietnamese battlefields. The implementation of chemical agents, especially herbicides, generated strong condemnations from anti-war activists as well as scientists and the worldwide population.

The confirmation of chemical warfare led to increased opposition against the war both domestically in the United States and internationally. Hostile critics attacked this technique because it was both cruel toward humans and damaging to the environmental surroundings. Agent Orange chemical spraying became the symbol of war devastation when scientists later discovered its connection to serious health problems affecting both Vietnamese civilians and American veterans and their offspring.

The announcement sparked discussions regarding warfare ethics along with its long-lasting effects on chemical weapon deployment during military engagements. The admission revealed the complex moral aspects of the Vietnam War operations, which eventually reduced American backing for US military engagement in the conflict.

The deployment of chemical weapons during the Vietnam conflict became a crucial element which brought catastrophic health impacts as well as permanent environmental destruction. Agent Orange cleanup projects, together with compensation initiatives for affected people, remain ongoing decades after the Vietnam War ended.