This is why you see a lot of public bathrooms with blue or purple lights.
https://abcnews.go.com/Health/blue-lights-drug-users-high/story?id=56140028
How blue lights can help drug users from getting high
Blue lights on skin make it harder to see surface veins.
It’s come to that, has it?
Blue lights on skin make it harder to see surface veins.
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How clever. But, of course, I see that opponents have all kinds of reasons why blue lights shouldn’t be used. I guess to them nothing should be used, and you should just accept drug addicts and/or homeless hanging around your home or business.