Russia is accused by the U.S. of violating the global chemical weapons ban through its alleged use in Ukraine.

• The U.S. accused Russia of using chemical weapons against Ukrainian troops.
• The Chemical Weapons Convention has been violated by Russia, which used "riot control agents," or tear gas, as a method of warfare in Ukraine, according to an assessment by the U.S. State Department.
• The State Department stated that the use of such chemicals is not a unique occurrence.

On Wednesday, the U.S. formally accused Russia of using chemical weapons against Ukrainian troops and announced new sanctions on Russian individuals and entities.

On Wednesday, the U.S. State Department issued a statement accusing Russia of violating the Chemical Weapons Convention by using chloropicrin, a choking agent, against Ukrainian forces.

In addition to our assessment that Russia has used riot control agents (tear gas) as a method of warfare in Ukraine, in violation of the CWC, we also determine that this use is not an isolated incident and is likely driven by Russian forces' desire to dislodge Ukrainian forces from fortified positions and achieve tactical gains on the battlefield.

Chloropicrin, once used as a poison gas in World War I, is now commonly used in agriculture as an insecticide. Although no longer authorized for military use, the "choking agent" primarily harms the respiratory tract, causing irritation to the nose, throat, and especially the lungs.

The Organisation for the Prohibition of Chemical Weapons states that when these agents are inhaled, they cause alveoli, the air sacs in the lungs, to secrete fluid, effectively drowning those affected.

In January, Ukraine accused Russia of employing chemical weapons in over 200 attacks on the battlefield. Russia refuted the accusations and countered by accusing Ukraine of using chemical weapons. Despite both sides making claims, no evidence has been presented to support either side's assertions, with soldiers reporting injuries from chemical agents.

The use of tear gas as a method of warfare is prohibited, yet both sides have accused each other of using it in the conflict.

The U.S. stated that Russia's employment of such weapons demonstrated a persistent disregard for its responsibilities under the CWC, a worldwide treaty prohibiting the manufacturing, storing, and utilization of chemical weapons.

The convention, which requires signatories to declare their banned chemical weapons and facilities and to strive to destroy them, was ratified by Russia, along with 192 other countries.

The State Department stated that the use of such weapons is consistent with Russia's approach to poisoning Kremlin opponents with Novichok nerve agents, as seen in the cases of Aleksey Navalny and Sergei and Yulia Skripal. Russia denied any involvement in these incidents.

CNBC has contacted the Kremlin for comment and is awaiting a response.

The US has declared three Russian government agencies and four companies as being linked to Russia's chemical and biological weapons programs.

The Treasury Department is imposing sanctions on three entities and two individuals who were involved in procuring items for military institutes linked to Russia's chemical and biological weapons programs.