Your hazmat training isn’t a one-and-done kind of thing. According to U.S. DOT hazmat training requirements, individuals are required to undergo hazmat training once every three years. That includes workers who have been employed in the hazmat industry for years. The importance of hazmat training makes it essential to keep employees updated with industry knowledge and safety guidelines. New employees must receive their hazmat certification within 90 days of their first shift. During this time, a trained employee must also supervise them. When an individual needs to renew their hazmat training, they will get a recertification notice. Air transport employees must train every two years as the Technical Instructions for Safe Transport of Dangerous Goods by Air is updated.