I would hate for anyone working in waste disposal to experience a needle stick and worry about transmissible diseases.
I take syringes to my doctor’s office and ask permission to use their sharps disposal bins. I have 4x/year follow-ups, so taking my once-monthly med syringes back isn’t a big deal.
The DC Department of Public Works has detail
instructions on proper sharps disposal:
https://dpw.dc.gov/sites/default/files/dc/sites/dpw/page_content/attachments/Proper_Disposal_of_Sharps_2009_11_19.pdf. And, yes, even retractable needles need to be disposed of properly.