My son asked this half an hour ago as we were getting our flu shot. The Ontario government sets up free clinics in schools for the shot and the empty hypos were placed in a hazmat kind of container but then what? Are they incinerated? That seems like it would create a lot of toxic smoke. Are they trucked to Newark and spread along the Jersey shore? How do you get rid of hundreds of thousands of these things?
Used hypodermics would be disposed of as a medical waste. They can be sent to a special medical waste incinerator (which most large hospitals have). Or they are sterilized then ground up for disposal in a landfill.
Medical waste incinerators burn very hot and have “scrubbers” on the smokestack so they don’t emit pollutants or worse, biohazardous fumes. Ideally, all that comes out the stack is heat and water vapor, leaving ash at the bottom.