I have to hand a guidebook by a lighting manufacturer Zumtobel Staff titled ‘Lighting for the Workplace’ that points to research from, among others, Brown University that reports that the brain has a non-visual light receptor most sensitive to blue light.

Exposure to blue light apparently causes the production of melatonin in the pineal gland to be suppressed, making us more alert, since melatonin makes us sleepy. In this context, they are attempting to convince us that expensive light fittings containing blue light in the workplace make for more productive employees, but annecdotally it’s no secret that alert shoppers spend more.

You can experiment with this effect yourself if, like me, you work or spend time in a building with little daylight. Though there are many factors that cause that afternoon lull, you will probably find this lull is less severe if you take an outdoor lunch break for at least 20 minutes.

I suppose what I meant was that if drug users still choose to inject under blue light and make mistakes, or need multiple tries, the effect on bystanders may be worse than if they did it more easily under normal light. There may be more discarded needles, blood, or worse.

But yes, overall, it would seem that the aim is to move the problem on.

I don’t see it so much here in bars as I do in places that have free entry and unattended washrooms, like laundromats and pizza-by-the-slice joints.

I don’t buy the idea that there’s a bystander effect like there is with the poor-visibility intersections, though. All things being equal, washrooms without drug users are safer and more comfortable for their intended use, and if drug users decide to use the washroom to shoot up anyhow, the blue light doesn’t make it more dangerous for the intended use than a washroom with regular lights.