Can this be used to seal a piece of sheet metal to a metal heated air duct? Should I be concerned about creating dangerous fumes in my heated air?

fumes? while cuirng, it is BAD. I got sick quick. after cured, it is fine.

Overview Flexible waterproof silicone sealant Use on metal, glass, wood and plastic Resists temperatures up to 316°C (600°F) Applications High Temperature Silicone Sealant for any application that requires a permanently flexible waterproof seal that will withstand moisture, heat and vibration. Adheres to clean metal, glass, most types of wood, ceramic, plastic, brick and slate. Fully cured, it can be used for extended periods at temperatures up to 260°C (500°F) and for shorter periods as high as 316°C (600°F). Directions TUBE: Surfaces must be clean and dry. Remove cap and cut nozzle to desired size opening. Apply by pushing sealant ahead of nozzle. Tool sealant immediately after application. Sealant can be applied in temperatures as low as –65°C (-85°F) provided the surfaces are dry and frost free. Dry to touch in 30 minutes; cures fully in 24 hours.