Well, its Syria all over again. Stage a chemical attack and open the door for US military intervention.
Ask yourself the question, Who would gain from a chemical attack in the Ukraine?
Russia could flatten the country of Ukraine just using its conventional weapons if it wanted. Russian knows that a chemical weapon attack would give the US/NATO the excuse they want to increase military intervention. There would be no advantage for Russia to use chemicals. None at all.
Don’t believe what you are being told. Be skeptical about everything you read, watch or hear. Think.