Unfortunately, chemical weapons are still being used by the Assad regime in Syria. The last attack which happened on 8th April 2018, killing at least 40 people in the eastern suburbs of Damascus in a town called Douma. That attack was almost exactly a year after a previous attack in the northern Syrian town of Khan Sheikhoun.
US intelligence agencies believe that Syria may have biological weapons. These weapons are not governed in the same way as chemical weapons. There is a Biological and Toxin Weapons Convention which Syria is a signatory to but any nation that would use chemical weapons on their own people probably would not hesitate to use biological weapons.