# Are blacklight posters dangerous?
**URL:** https://boards.straightdope.com/t/are-blacklight-posters-dangerous/664362
**Category:** Factual Questions
**Created:** [July 24, 2013, 5:58am UTC](https://boards.straightdope.com/t/are-blacklight-posters-dangerous/664362 "2013-07-24T05:58:23Z")
**Posts on this page:** 20
**Page:** 1
### Author:  [@john44](https://boards.straightdope.com/u/john44)
#### Post date: [July 24, 2013, 5:58am UTC](https://boards.straightdope.com/t/are-blacklight-posters-dangerous/664362/1 "2013-07-24T05:58:23Z")
I was thinking of buying a blacklight poster so I looked them up and wikipedia says they contain phosphors as ink. I always thought phosphors (such as trisodium phosphate) were strongly alkaline, even caustic to skin. Can handling a black light poster cause skin irritation from the phosphors?
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### Author:  [@colander](https://boards.straightdope.com/u/colander)
#### Post date: [July 24, 2013, 6:11am UTC](https://boards.straightdope.com/t/are-blacklight-posters-dangerous/664362/2 "2013-07-24T06:11:49Z")
> [@john44](#):
>
> I was thinking of buying a blacklight poster so I looked them up and wikipedia says they contain phosphors as ink. I always thought phosphors (such as trisodium phosphate) were strongly alkaline, even caustic to skin. Can handling a black light poster cause skin irritation from the phosphors?
You should go for it. Phosphates and phosphors are not directly related; a phosphor is just a molecule that is able to phosphoresce.
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### Author:  [@njtt](https://boards.straightdope.com/u/njtt)
#### Post date: [July 24, 2013, 7:10am UTC](https://boards.straightdope.com/t/are-blacklight-posters-dangerous/664362/3 "2013-07-24T07:10:51Z")
There seem to be a lot of misconceptions in this question. As **colander** says, phosphors and phosphates are not the same thing - phosphors are just substances that glow in the dark, and do not necessarily contain phosphorus at all - but even if phosphors were phosphates, phosphates in general and trisodium phosphate in particular are not inherently dangerous. Your bones are largely made of phosphate, as is your DNA, and trisodium phosphate used to be added to soaps and detergent (and it is still used to some extent as a food additive). Its use in cleaning products was largely discontinued, but not because it was directly harmful to humans. The problem with it was ecological. It is an effective fertilizer, and when the stuff from detergent got into waterways as a pollutant it caused algal blooms, choking the waterways with weed and removing the oxygen need by fish from the water.
The nasty stuff is elemental phosphorus. This is very poisonous, and, in its white allotrope, slowly but spontaneously burns when exposed to air, and is very difficult to extinguish. (The fact that it slowly burns makes it glow in the dark, so it was the earliest known form of phosphor, which explains why both words have the same root, but many other non-phosphorous phosphors are known today, including those in black light posters.) If white phosphorus gets on your skin it will burn you, and it tends to stick to flesh, so it can be very difficult to get off, and may burn in deeply. You won’t find any of it on black light posters, though.
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### Author:  [@john44](https://boards.straightdope.com/u/john44)
#### Post date: [July 24, 2013, 9:03am UTC](https://boards.straightdope.com/t/are-blacklight-posters-dangerous/664362/4 "2013-07-24T09:03:58Z")
> [@njtt](#):
>
> There seem to be a lot of misconceptions in this question. As **colander** says, phosphors and phosphates are not the same thing - phosphors are just substances that glow in the dark, and do not necessarily contain phosphorus at all - but even if phosphors were phosphates, phosphates in general and trisodium phosphate in particular are not inherently dangerous. Your bones are largely made of phosphate, as is your DNA, and trisodium phosphate used to be added to soaps and detergent (and it is still used to some extent as a food additive). Its use in cleaning products was largely discontinued, but not because it was directly harmful to humans. The problem with it was ecological. It is an effective fertilizer, and when the stuff from detergent got into waterways as a pollutant it caused algal blooms, choking the waterways with weed and removing the oxygen need by fish from the water.
>
> The nasty stuff is elemental phosphorus. This is very poisonous, and, in its white allotrope, slowly but spontaneously burns when exposed to air, and is very difficult to extinguish. (The fact that it slowly burns makes it glow in the dark, so it was the earliest known form of phosphor, which explains why both words have the same root, but many other non-phosphorous phosphors are known today, including those in black light posters.) If white phosphorus gets on your skin it will burn you, and it tends to stick to flesh, so it can be very difficult to get off, and may burn in deeply. You won’t find any of it on black light posters, though.
Yes trisodium phosphate used to be in detergent but it was rinsed out. If they use it as a dye it will remain in it.
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### Author:  [@njtt](https://boards.straightdope.com/u/njtt)
#### Post date: [July 24, 2013, 9:49am UTC](https://boards.straightdope.com/t/are-blacklight-posters-dangerous/664362/5 "2013-07-24T09:49:06Z")
> [@john44](#):
>
> Yes trisodium phosphate used to be in detergent but it was rinsed out. If they use it as a dye it will remain in it.
The point is that it is not dangerously “caustic”, as you suggested, or otherwise particularly dangerous. It was not removed from detergents because it was a direct hazard to human health, but for other reasons. Even if it _were_ used in black light posters (which it almost certainly isn’t) it would not make them dangerous.
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### Author:  [@john44](https://boards.straightdope.com/u/john44)
#### Post date: [July 24, 2013, 10:39am UTC](https://boards.straightdope.com/t/are-blacklight-posters-dangerous/664362/6 "2013-07-24T10:39:39Z")
> [@njtt](#):
>
> The point is that it is not dangerously “caustic”, as you suggested, or otherwise particularly dangerous. It was not removed from detergents because it was a direct hazard to human health, but for other reasons. Even if it _were_ used in black light posters (which it almost certainly isn’t) it would not make them dangerous.
The msds for it says it is caustic.
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### Author:  [@lazybratsche](https://boards.straightdope.com/u/lazybratsche)
#### Post date: [July 24, 2013, 11:05am UTC](https://boards.straightdope.com/t/are-blacklight-posters-dangerous/664362/7 "2013-07-24T11:05:47Z")
MSDS’s tend to be very over-cautious. You’re probably seeing something that says “may cause skin burns”. In truth, that’ll only happen if you grind a handful of it into an open wound. It’s probably exactly as dangerous as, say, rock salt. You’d regret it if you got it in your eyes, but otherwise just use a bit of common sense and wear gloves when you’re handling large quantities.
Sodium phosphate is also commonly used in [buffer solutions](http://en.wikipedia.org/wiki/Buffer_solution), to keep the pH in a certain range. In fact, a lot of things like **eye drops** (which is as harmless as anything can get!) are basically saline buffered with phosphate or something similar to make the pH neutral.
In the case of the black light dyes, it may be that some dyes are naturally acidic, which is counteracted and buffered by the addition of the basic forms of sodium phosphate to give a neutral dye solution. That’s a WAG on my part, but I am aware of plenty of dyes that need pH adjustments to dissolve effectively or “fix” to whatever is being dyed.
Though of course, I’ll repeat that “phosphor” are _not_ the same as the (very very mildly hazardous) sodium phosphate.
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### Author:  [@beowulff](https://boards.straightdope.com/u/beowulff)
#### Post date: [July 24, 2013, 12:35pm UTC](https://boards.straightdope.com/t/are-blacklight-posters-dangerous/664362/8 "2013-07-24T12:35:37Z")
Are you planning on eating your poster?
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### Author:  [@Czarcasm](https://boards.straightdope.com/u/Czarcasm)
#### Post date: [July 24, 2013, 12:46pm UTC](https://boards.straightdope.com/t/are-blacklight-posters-dangerous/664362/9 "2013-07-24T12:46:42Z")
> [@john44](#):
>
> The msds for it says it is caustic.
It still isn’t used in black light posters, so it doesn’t matter.
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### Author:  [@Koxinga](https://boards.straightdope.com/u/Koxinga)
#### Post date: [July 24, 2013, 12:51pm UTC](https://boards.straightdope.com/t/are-blacklight-posters-dangerous/664362/10 "2013-07-24T12:51:24Z")
> [@njtt](#):
>
> As **colander** says, phosphors and phosphates are not the same thing
On the other hand, if these black light posters inspire you have any wild house parties with a lot of people crowded into a small space, be aware that you could catch rabies.
Especially if any of them seem particularly itchy.
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### Author:  [@Jackmannii](https://boards.straightdope.com/u/Jackmannii)
#### Post date: [July 24, 2013, 12:51pm UTC](https://boards.straightdope.com/t/are-blacklight-posters-dangerous/664362/11 "2013-07-24T12:51:50Z")
Do not bathe in the chemicals used to create your poster.
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### Author:  [@Thudlow\_Boink](https://boards.straightdope.com/u/Thudlow_Boink)
#### Post date: [July 24, 2013, 1:07pm UTC](https://boards.straightdope.com/t/are-blacklight-posters-dangerous/664362/12 "2013-07-24T13:07:01Z")
> [@njtt](#):
>
> The nasty stuff is elemental phosphorus. This is very poisonous, and, in its white allotrope, slowly but spontaneously burns when exposed to air, and is very difficult to extinguish.
Nasty indeed. [Doctor Phosphorus](http://images3.wikia.nocookie.net/__cb20061110172202/marvel_dc/images/1/17/Detective_Comics_469.jpg) creeped me the f\*\*\* out when I encountered him in a comic book as a kid.
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### Author:  [@ducati](https://boards.straightdope.com/u/ducati)
#### Post date: [July 24, 2013, 1:11pm UTC](https://boards.straightdope.com/t/are-blacklight-posters-dangerous/664362/13 "2013-07-24T13:11:01Z")
Do no taunt phosphors.
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### Author:  [@kayaker](https://boards.straightdope.com/u/kayaker)
#### Post date: [July 24, 2013, 1:32pm UTC](https://boards.straightdope.com/t/are-blacklight-posters-dangerous/664362/14 "2013-07-24T13:32:34Z")
Not certain if it is cause/effect, but everyone I know that had black-light posters has gotten very old.
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### Author:  [@Fear\_Itself](https://boards.straightdope.com/u/Fear_Itself)
#### Post date: [July 24, 2013, 1:35pm UTC](https://boards.straightdope.com/t/are-blacklight-posters-dangerous/664362/15 "2013-07-24T13:35:46Z")
Where does one buy black light posters these days?
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### Author:  [@DrFidelius](https://boards.straightdope.com/u/DrFidelius)
#### Post date: [July 24, 2013, 1:39pm UTC](https://boards.straightdope.com/t/are-blacklight-posters-dangerous/664362/16 "2013-07-24T13:39:06Z")
> [@kayaker](#):
>
> Not certain if it is cause/effect, but everyone I know that had black-light posters has gotten very old.
Back in my day, I saw a high correlation between black light posters and giggling, lethargy, paranoia, hunger, and short-term memory issues.
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### Author:  [@DrFidelius](https://boards.straightdope.com/u/DrFidelius)
#### Post date: [July 24, 2013, 1:41pm UTC](https://boards.straightdope.com/t/are-blacklight-posters-dangerous/664362/17 "2013-07-24T13:41:58Z")
> [@kayaker](#):
>
> Not certain if it is cause/effect, but everyone I know that had black-light posters has gotten very old.
Back in my day, I saw a high correlation between black light posters and giggling, lethargy, paranoia, hunger, and um, something else . . ..
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### Author:  [@Darth\_Panda](https://boards.straightdope.com/u/Darth_Panda)
#### Post date: [July 24, 2013, 1:47pm UTC](https://boards.straightdope.com/t/are-blacklight-posters-dangerous/664362/18 "2013-07-24T13:47:39Z")
> [@DrFidelius](#):
>
> Back in my day, I saw a high correlation between black light posters and giggling, lethargy, paranoia, hunger, and short-term memory issues.
Most of that can be caused by Fox News.
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### Author:  [@johnpost](https://boards.straightdope.com/u/johnpost)
#### Post date: [July 24, 2013, 2:15pm UTC](https://boards.straightdope.com/t/are-blacklight-posters-dangerous/664362/19 "2013-07-24T14:15:04Z")
you would be dead without your phosphates.
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### Author:  [@aruvqan](https://boards.straightdope.com/u/aruvqan)
#### Post date: [July 24, 2013, 3:27pm UTC](https://boards.straightdope.com/t/are-blacklight-posters-dangerous/664362/20 "2013-07-24T15:27:36Z")
> [@johnpost](#):
>
> you would be dead without your phosphates.
or living as a blob in a bucket like[Odo](http://en.memory-alpha.org/wiki/Odo%27s_bucket) …
I have [CPPD](http://en.wikipedia.org/wiki/Chondrocalcinosis), where my phosphates are frisky and about 10% or so deposit in the joints in my feet instead of in my bones where they are supposed to go to live. I do wish they would behave … ☹
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