Are fluorescent dyes radioactive?

[justamom]

TL;DR Summary

Are fluorescent neon clothing like those used for construction workers(Hi Visability vests) radioactive?

I noticed the construction workers and gardeners and road construction workers wear neon green vests that look fluorescent, how are the dyes for those clothing made? Are they radioactive?

 

[pinball1970]

Summary:: Are fluorescent neon clothing like those used for construction workers(Hi Visability vests) radioactive?

I noticed the construction workers and gardeners and road construction workers wear neon green vests that look fluorescent, how are the dyes for those clothing made? Are they radioactive?

No. They absorb light at the UV end and throw it out at the visible light end.
So 400nm or less then emit at 400 plus where we can see it. Roughly.
@sophiecentaur best for his I think

 

[DaveE]

No. They could be if they were made with radioactive atoms, but they are not. That would be too expensive, among other problems. Fluorescence, bright colors, and radioactivity are all separate things. https://en.wikipedia.org/wiki/Fluorescence

 

[sophiecentaur]

Roughly.
@sophiecentaur best for his I think

You'll have to help me with this, I think.

 

[Astronuc]

Summary:: Are fluorescent neon clothing like those used for construction workers(Hi Visability vests) radioactive?

how are the dyes for those clothing made? Are they radioactive?

Flourescent dyes are organic molecules, made by chemical processes and designed based on the fabric/textile to which they will be applied. They are NOT radioactive since they do not emit light unless light is incident on the dye, besides the fact that radioactive atoms are not added to commercial products.

Fluorescent dyes show a behavior in which a molecule transitions to an excited state by the light energy of the absorbed wavelength, and then the absorbed light energy is again emitted as a longer wavelength that returns the molecule to a stable bottom state. Several reports have evaluated the fluorescence intensity of florescent dyes based on dye fastness (Kim et al. 2017). The purpose of using fluorescent dyes is high visibility due to the emission of light;

Ref: https://fashionandtextiles.springeropen.com/articles/10.1186/s40691-019-0190-4

It's complicated chemistry, but the dyes are not radioactive.
https://www.sciencedirect.com/topics/chemistry/fluorescent-dye

 

[pinball1970]

Summary:: Are fluorescent neon clothing like those used for construction workers(Hi Visability vests) radioactive?

I noticed the construction workers and gardeners and road construction workers wear neon green vests that look fluorescent, how are the dyes for those clothing made? Are they radioactive?

Just to add from the guys above
Sometimes better with a few illustrations
Fluorescent / high vis clothing looks bright in day light because day light has a UV content that activates the dyes/pigments
A light box below with dye/pigment samples. The light source is D65- artificial daylight so there will be UV content in there
Pigments on the left, dyes on the right, left is fluorescent right is "normal" dyes

Switch the light source UV only which is barely visible to human eye and only the fluorescent pigments are visible.
Also notice there is some fluorescence on the paper on the left?

You can add an FWA/OBA (fluorescent whitening agent or an Optical brightening agent) to paper pulp- it gives it a bluish whiteness.
Similar thing in washing powder for whites.

 

[sophiecentaur]

Summary:: Are fluorescent neon clothing like those used for construction workers(Hi Visability vests) radioactive?

how are the dyes for those clothing made? Are they radioactive?

The energy from radioactivity (each individual event) is very high so it can do damage to cells and cause all sorts of chemical changes. But those dayglo dyes react to UV photons which have energies only slightly above visible light (and they don't produce UV - they just use what's present in sunlight).
You 'could say' that the only possible danger to the wearer is due to the sunlight they're standing in. That can, of course, be relevant as we can suffer from skin cancers and cataracts (been there in both cases!) but it's nothing to blame the dyes for.

 

[Janus]

As a side note. There was a time when they used radium to make watches that could be read in the dark. (Modern "glow in the dark" watches uses luminescence, which works by storing light energy to release it later).
The practice of using radium did lead to workers, whose job it was to paint the watch dial, to suffer from radiation poisoning.

 

[Astronuc]

As a side note. There was a time when they used radium to make watches that could be read in the dark. (Modern "glow in the dark" watches uses luminescence, which works by storing light energy to release it later).
The practice of using radium did lead to workers, whose job it was to paint the watch dial, to suffer from radiation poisoning.

And some of the sites where this happened are still contaminated, and some of the women were so 'radioactive' that they had to be buried in lead lined coffins. Radium is chemically similar to calcium, so it is readily taken into the bones and teeth. To make matters worse, several isotopes (radionuclides) of Ra decay to Rn, the Po, and eventually Pb, all of which have toxicity as heavy metals, as well as the radioactivity, which is why it is no longer used as it was in the past, and certainly not in consumer products.

There are radioluminescent compounds, but they are limited to special applications, not consumer products.

https://en.wikipedia.org/wiki/Radium_dial
https://en.wikipedia.org/wiki/Radium_Girls

Radium-based luminescent paint is no longer used due to the radiation hazard posed to those manufacturing the dials.
https://en.wikipedia.org/wiki/Radioluminescence
According to the article, "The latest generation of radioluminescent materials is based on tritium, a radioactive isotope of hydrogen with half-life of 12.32 years that emits very low-energy beta radiation. It is used on wristwatch faces, gun sights, and emergency exit signs." However, it is not used in luminescent clothing.

 

[sophiecentaur]

And the site where this happened is still contaminated, and some of the women were so 'radioactive' that they had to be buried in lead lined coffins.

Absolutely disgusting behaviour of the Westclocks company. They fought the case for ages, despite the obvious suffering of the former 'girls' and the early deaths of many of them. I remember a BBC documentary about it.

 

[anorlunda]

After radium, they used tritium. Also very hazardous stuff.

 

[Rive]

After radium, they used tritium. Also very hazardous stuff.

Tritium emits low energy beta radiation. That is: simple electrons.
Sure: not expected to be nice if ingested, but 'very hazardous' in general? Just - no.

And some of the sites where this happened are still contaminated

Also, there are some antique items dating back to the beginning of the 19's which may be considered hazardous and may require special attention.

Usually they are fairly safe if left alone, though. But for example I know about a case when somebody tried to 'neutralize' his vintage clock collection by dissolving and removing >>that<< paint

Also, as I recall in those times right after Fukushima lot of people started to look for 'hot spots' in Japan.
A really interesting find was some buried paints in Tokyo.

 

[sophiecentaur]

Tritium emits low energy beta radiation. That is: simple electrons.
Sure: not expected to be nice if ingested, but 'very hazardous' in general? Just - no.

I seem to remember a mate of mine had a luminous digital watch with a so-called Betalight background. That was in the mid eighties iirc.
Radioactivity is a topic that tends to be treated with an amazing level of suspicion. The background level in some areas of the country with igneous rocks is higher than some of the acceptable industrial and consumer standards. But I guess as no one can be 'blamed' for it, no one need fear litigation so people just accept the risk.

 

[anorlunda]

Sure: not expected to be nice if ingested

But ingestion of tritiated water is exactly the hazard.

http://hps.org/documents/tritium_fact_sheet.pdf

For this reason, the beta particle emitted by tritium is generally only considered to be hazardous if a large quantity of tritium is, or has the potential to be, taken into the body by inhalation, skin absorption, and ingestion of tritiated water.

https://en.wikipedia.org/wiki/Tritium#cite_note-41
According to the U.S. Environmental Protection Agency, self-illuminating exit signs improperly disposed in municipal landfills have been recently found to contaminate waterways.

And news from 1979.

https://occupiedtucsoncitizen.org/?p=6256
Early this year, the Arizona AEC began listening to employee complaints about radiation hazards at American Atomics. Follow-up investigations revealed that up to 85 times the maximum permissible amount of tritium had escaped the plant. The next discovery drew nationwide attention: the school kitchen down the block from American Atomics was checked out and a cake, intended for a school lunch, was found to contain alarming amounts of tritium.

The community was stunned. School children all over town had apparently been eating food contaminated with radiation for some time. National media jumped all over the story, but the public didn’t need to hear more to decide what to do about American Atomics; they wanted to shut it down. But instead of the plant halting production, the kitchen closed and the kids started brown-bagging it to school, while various branches of state and local government wondered who had the power to do what about American Atomics.

Tritium was showing up all over the neighborhood. It was in the senior citizens’ jello. It was in the Catholic school’s swimming pool. Special clinics were set up to test samples of food, water and urine.

 

[Rive]

But ingestion of tritiated water is exactly the hazard.

The hazard is what it can cause - and in what quantities.
What you will find about that is a massive amount of lack of reliable data.
Mainly, the effect is so different to what Radium can do, that putting together the two as 'also very hazardous stuff' is kind of like that dihidrogen-monoxide joke.

And news from 1979.

Good read, but where are the dangers?

 

[anorlunda]

Good read, but where are the dangers?

You're correct. I looked up the NRC's page on tritium dose limits.
https://www.nrc.gov/reading-rm/doc-collections/fact-sheets/tritium-radiation-fs.html#risks

It cites only the ALARA (As Low As Reasonably Achievable) standard, which means a restriction with no justification at all.

I fell into the trap of assuming a rational basis to government regulations.

 

[Astronuc]

Good read, but where are the dangers?

Tritium, T = ³H, behaves chemically as H, or D (²H), and so can undergo isotopic exchange in molecules or compounds containing H. Water and Organic molecules in a cell could have their H atoms exchanged with T. At some later time, T decays by beta emisson to ³He, so that molecule becomes slightly dehydrogenated, thus changing the chemical nature. Then there is the radiological aspect in which the low energy beta with maximum energy of approximately 18 keV and an average energy of approximately 5.7 keV, which is relatively low energy, but enough to ionize many atoms/molecules in a cell, some of which are oxidative species that could chemically interact with other molecules, such that those molecules change structure. This is why penetrating radiation or radionuclides ingested into the body represent a biological hazard.

 

[Rive]

ALARA (As Low As Reasonably Achievable) standard, which means a restriction with no justification at all.

That's a bit too strong. I did not want to convey anything like 'tritium is harmless' or so, not at all. We do know that it may cause problems (at very high doses and with very long time of exposure). @Astronuc brought the mechanism for that.

My point is, that Tritium and Radium are not comparable. The phrase of 'also a very hazardous stuff' is very misleading in this context.

 

[Astronuc]

It cites only the ALARA (As Low As Reasonably Achievable) standard, which means a restriction with no justification at all.

Further in the NRC article cited, it states

The NRC sets dose limits for radiation workers and the general public well below the levels of radiation exposure that cause health effects in humans – including a developing embryo or fetus. The effects of high doses and high dose rates are well understood. Public health research, however, has not established health risks at low doses and low dose rates – below about 10,000 mrem.

The NRC calculated a maximum annual dose of less than 0.1 mrem to a member of the public from a significant tritiated water spill at the Braidwood Station nuclear power plant in Illinois. This dose is well below the NRC's 500 mrem dose limit for declared pregnant workers at nuclear facilities and the 100 mrem annual dose limit for members of the general public.

So there are maximum limits established for each radionuclide as well as a maximum dose to members of the public. ALARA acknowledges that there is a dose, that there are limits, and one cannot achieve 'zero' amount of material, i.e., zero contribution to the total dose. In ALARA, one is expected to ensure the radioactivity is below the allowable limit, preferably well below, as reasonably achievable.

Tritium and Radium are not comparable

True. I don't believe anyone claimed otherwise. Each radionuclide must be considered individually in conjunction with the total dose. The radionuclides of heavy elements (Pb and beyond) are especially dangerous because heavy metal are chemically toxic (most are neurotoxic) and as the Z increases, it means there are more decays to go through, e.g., Ra -> Rn -> Po, and so on.

 

[cmb]

Summary:: Are fluorescent neon clothing like those used for construction workers(Hi Visability vests) radioactive?

I noticed the construction workers and gardeners and road construction workers wear neon green vests that look fluorescent, how are the dyes for those clothing made? Are they radioactive?

No, not radioactive. So radioactivity is not really the thing you were asking. ( )

Hi viz jackets usually have two components, one material with a fluorochrome and usually another stitched on top in strips with a retroreflective material.

Fluorochromes work because of the electron configurations in the molecules, the bonds absorb higher energy photons, then some energy is lost and re-radiated at a lower wavelength. The first such dye material was fluoresin first made back in the 1880s or so and is still widely used, afaik.

This is different to those crack-open type illumination/party sticks, which will actively generate light emissions via 'an interesting' chemical reaction. You can look that up to find out why it is so interesting.

The second material on a jacket are optically reflective materials to reflect any light back at you, so if you are the source of the light (e.g. sitting in a car with your headlights on) the retroreflective material in the jacket of the worker's hiviz you are approaching may be, for example, lots of little cubic transparent pieces that will reflect your light back at you. Obviously, a fluorochrome will not work in darkness whereas a retroreflective will continue to do its job so long as there is an oncoming light source.

In situations where it is night time and there are no other sources of light to be reflected, workers carry safety lanterns! These are usually powered by the battery and no-one has yet produced a nuclear powered lantern in general use, but it is not an impossible thing and there are examples; like tritium safety lights, one would look for a pure beta emitter with low energy betas (e.g. tritium, but it is also a gas which is problematic) and the emitted betas cause a phosphorescence in a material which, like the fluorochromes, receive the energy excitation this time from betas (extra electrons) instead of photons, then re-radiate a photon in a likewise manner. Radium is such a beta source but it also comes with an even larger dose of gammas.

Fluorochromes are often good for electron-stimulated phosphorescence, for all the same reasons that their electron configurations can be stimulated to re-radiate visible light. So, exposing a worker in a hi viz to a beam of betas from a large radioactive source would also probably make them glow, but they might prefer you just pointed a headlight at them. ;)

 

[Astronuc]

So radioactivity is not really the thing you were asking.

Actually, it is. The OP is concerned about radiation, hence the question.

Summary:: Are fluorescent neon clothing like those used for construction workers(Hi Visability vests) radioactive?

Are they radioactive?

We have answered that reflective or luminescent material is generally not radioactive, and luminescent dyes are chemical, or photochemical, in nature. For clothes/garments, the dyes would not contain a radionuclide, at least not intentionally outside of normal background activity.

https://www.rp-photonics.com/photoluminescence.html (irradiation refers to generic photons on the surface or object, which then produces photoexcitation).
https://en.wikipedia.org/wiki/Photoluminescence