Actually, search your city/county waste website. I wish I had the link to prove it, but my city says an appropriate, and legal, way to get rid of diabetic insulin needles is to place them in a sturdy plastic or metal container, like a coffee tin, laundry detergent bottle, with a lid and duct tape around the lid. Then throw the bottle in the trash. Just make sure it is securely sealed.
After it hits the trash compactor, I don't know, but maybe no one would come in contact with the trash. (no clue how the system works).
Although, a needle exchange or sharps container would probably be a better idea.