There is no definitive answer to this question as it depends on the specific concentration of Sevin dust in the environment. However, according to the Environmental Protection Agency, Sevin dust can be a potentially toxic chemical. Sevin dust is a white, powdery, crystalline material that is used in the production of a number of industrial products, including cigarettes and asbestos. It can be harmful to the environment and human health if breathed in, and can cause cancer in humans.