firework tubes - does any body know?

does anyone know if those firework leftover tubes would have chemicals in them that might be dangerous to bees? or not? as they seem like just about the right size and already in groups that might work for mason bees, but NOT if they are dangerous for them..my son blew off a bunch of fireworks and I'm wondering if saving those groups of tubes for bees would be good..or bad?

Take one whiff of them, and then ask yourself "Would I like to live there and raise a family?"

good point..thanks