blue light
Blue neon lights were successfully used in public bathrooms and publicly accessible toilets, as a means of preventing drug users from injecting themselves. Because it makes veins harder to see, it is expected that drug users will stop using these bathrooms for the aforementioned purpose.
![blue-light-toilet-men](http://unpleasant.pravi.me/wp-content/uploads/2011/09/blue-light-toilet-men.jpg)
Blue lights used in the public toilet in The Hague City Hall; men's toilet
![blue-light-toilet-women](http://unpleasant.pravi.me/wp-content/uploads/2011/09/blue-light-toilet-women.jpg)
Blue lights used in the public toilet in The Hague City Hall; women's toilet
further reading:
http://www.theargus.co.uk/archive/1999/02/18/The+Argus+Archive/
http://news.bbc.co.uk/2/hi/uk_news/england/cambridgeshire/3147170.stm