Risk is obviously much higher if you re-use the needles to inject drugs. Casual contact with the needle is low risk.
That's assuming lots of needles. I see needles sometimes. I use the 311 app when I see needles. But I don't see them in an area where my kids are going to play.
But, I've heard that risk from casual contact with hypodermic needles is rare. See: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2529409/
Risk is obviously much higher if you re-use the needles to inject drugs. Casual contact with the needle is low risk.
That's assuming lots of needles. I see needles sometimes. I use the 311 app when I see needles. But I don't see them in an area where my kids are going to play.