This is a K-51 CS gas grenade: https://cat-uxo.com/explosive-hazards/grenades/k-51-hand-grenade
Here is it being used by 109 OGSHB about 3 months ago to great effect: https://www.reddit.com/r/CombatFootage/comments/10zg9tc/109_ogshb_using_k51_cs_gas_grenade_with_great/
Regular smoke grenades are usually in a metal canister. There is nothing wrong with using military grade cs on the battlefield.
The Russians although have been accused of using it mixed with chloropicrin (chem agent from ww1). You can read about that here, it's pretty interesting: https://www.forbes.com/sites/davidhambling/2022/11/01/yes-these-are-chemical-weapons-why-russias-tear-gas-bombings-in-ukraine-matter/?sh=70ae524838b0