In November, the United States Border Patrol had one of its first encounters with the migrant caravan from Honduras, when United State border officials launched multiple canisters of Tear Gas into the Mexican border regions. The gas was utilized in an effort to prevent the caravan from crossing the border. Tear gas is a chemical compound commonly used as a riot suppressant. Because the gas is banned in warfare, its use has led to many questions on the legality and morality of the United States’ decision to use the compound on the border.

Tear gas, also known as mace or lacrimator, is designed to cause irritation of the mucous membranes causing coughing, tearing of the eyes and burning in the eyes, nose and throat. It is a nonlethal agent mainly used to minimize harm to civilians and de-escalate violent situations. Tear gas can also cause death; however, this is rare and only results from long-term exposure in unventilated areas.

Tear gas has been banned in use in warfare since 1993 under the Chemical Weapons Convention. This ban is primarily in effect to prevent those exposed to tear gas from mistaking it for deadlier form of chemical weapon such as sarin gas and responding in kind. Tear gas can be stored for the purpose of riot control and as a tool to train military personnel, but these stores must be declared to the international community. Although the United States’ launching of tear gas into Mexico could be perceived as a threat to Mexico’s sovereignty, it is unlikely that Mexico will pursue charges against the United States of America in an international court of law.  

The use of tear gas also raises ethical questions. Critics such as Jamal Dakwar , the director of the American Civil Liberties Union’s human rights program, claim that this use of tear gas was an unnecessary use of force against vulnerable refugees, including children.  

Defenders of its use such as Rodney Scott, a border control chief, say that the border control officers were facing “a direct and immediate threat” and that it was necessary in order to prevent harm from coming to United States personnel.

The migrants who were tear gassed have created a camp not far from the United States border. It is unclear how the caravan of 5,000 will be processed into the country.