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A user over on Home Improvement asked How to deal with broken compact fluorescent (and its mecury) without breaking the bank? with emphasis on the mercury which such lamps contain.

I had a vague recollection of something I'd heard a few years ago and a quick search led to me leaving a comment:

Gloves to avoid getting a cut are a good idea as the phospor-containing coating on the inside of the glass can stop blood from clotting: The dangers from phosphor-coated glass of broken CFL bulbs.

Another user pointed out:

this is the first I've read about the anti-clotting effect of phosphors, and I can't find an independent source. Do you know of one?

So I went looking for more information and it seems that all articles I can find on the Internet mentioning the danger of the phosphor coating have wording derived from The Fluorescent Lighting System, which states:

The biggest immediate injury threat from a broken lamp is from the phosphor-coated glass. If cut with fluorescent lamp glass, any phosphor that gets into the wound is likely to prevent blood clotting and will interfere with healing.

I have contacted the author of that article to ask if they can supply a reference for that information.

An article in Scientific American mentions only the mercury and not the phosphors: Are Compact Fluorescent Lightbulbs Dangerous? I would have thought that SA would mention a problem with the phosphors if there was one.

There is anecdotal evidence at Cut by a broken CFL that it isn't that harmful (in the bleeding sense), and contributor retiredsparktech there suggests that it was arsenic-containing phospors which were to blame

So, are, or at any time were, the phosphors in fluorescent lamps anticoagulant, and if so would it be to a dangerous extent?

Andrew Morton
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    Your question is kind of muddled; you are forgetting to add the critical bit to **any** question of the sort "Is substance X dangerous?", and that is "At what **doses** are substance X dangerous?". Ever since [Paracelsus](https://en.wikipedia.org/wiki/Paracelsus) we know that [*"The dose makes the poison"*](https://en.wikipedia.org/wiki/The_dose_makes_the_poison). So in your particular case your question becomes: "Can a person be subjected to substances from a broken low energy light, to such a dose that it becomes an acute hazard to their health?". –  Jan 08 '18 at 14:04
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    Glass doesn't really show up in an x-ray, which makes things like the [Glasmine 43](https://en.wikipedia.org/wiki/Glasmine_43) such a bugger. *Any* glass inside the body is somewhat of a threat to your overall health, and the glass from a CFL (or *any* lightbulb really) is fragile and sharp, thus difficult to remove from a wound. So, what's "a dangerous extend" of injury added by any coating, that isn't already there due to the glass alone? (What Michael said, basically -- he beat me to it.) – DevSolar Jan 08 '18 at 14:05
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    @MichaelKarnerfors: It is more specific that that. Can a person be subjected to **phosphor** from a broken low energy light, to such a dose that it **acts as an anticoagulant**, causing an (even mild) hazard? This in on top of the physical hazards due to sharp glass fragments and due to mercury. – Oddthinking Jan 08 '18 at 14:09
  • @Oddthinking Yes, that is exactly what I thought I wrote. I'd be happy to edit your wording into the question if you think it will make it easier to understand. – Andrew Morton Jan 08 '18 at 14:13
  • @DevSolar If the coating was a 100% effective anticoagulant then getting some in a cut could lead to death by exsanguination. If it really was that effective then I think it is unlikely that it would be allowed. Or maybe it is that effective but gets flushed out very easily. – Andrew Morton Jan 08 '18 at 14:18
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    Low energy lights are not coated by "phosphor". They are coated by several **phosphor compounds**. Several are needed because each compound usually gives only one colour of light. Googling for phosphor and clotting, the only thing I can find is that phosphor is **beneficial** for blood clotting, and a necessary substance for clotting to take place. Regarding phosophor compounds used in low energy lights, I find nothing. Also I think that this is **not** a notable claim since the site that is referred to make the claim does not even exist any more. –  Jan 08 '18 at 14:31
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    @MichaelKarnerfors: Most of that comment is a pseudo-answer. Add references, and make it an answer. The non-notable part is a good point. Can we find some other sources of this claim to show it notable. – Oddthinking Jan 08 '18 at 14:38
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    @MichaelKarnerfors The site http://nemesis.lonestar.org/reference/electricity/fluorescent/safety.html works for me. For "phosphor and clotting", did the article refer to phospors or phosphorus? The two are not the same. – Andrew Morton Jan 08 '18 at 14:42
  • @AndrewMorton It is the same text but I see no references from that site to support the claim. How is this then a notable claim? –  Jan 08 '18 at 14:46
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    @MichaelKarnerfors Do I not have enough people saying about it for it to be a notable claim? There is the website I linked to which stated it is a problem and two people at the electriciantalk.com website say they have heard of it being a problem. I was prepared to believe the claim until [Spencer Joplin](https://diy.stackexchange.com/users/64533/spencer-joplin) questioned its truth. – Andrew Morton Jan 08 '18 at 15:02
  • @AndrewMorton What, you are prepared to believe a claim just because it is on a website, and you did not even bother to Google it? As for notable claims, the help section for Skeptics SE will tell you what constitutes a notable claim. :-) –  Jan 08 '18 at 15:05
  • @MichaelKarnerfors I had heard the claim a long time ago and thought I could have mis-remembered something so I had a look on Google and found pages with the same claim. The tour told me "Ask about... the accuracy of public claims made in the media or elsewhere." – Andrew Morton Jan 08 '18 at 15:10
  • http://www.armourtownship.ca/_literature_131128/2015_TRI-R_Flyer also reproduces the claim verbatim, along with half-dozen sites (most of them rubbish though) Also https://sites.google.com/site/metropolitanforensics/what-are-the-connections-between-mercury-uv-emissions-phenol-emissions-and-compact-fluorescent-light-lamps-cfls pretends to be a real forensic business and has the same info. So I think the claim is notable enough. – Fizz Jan 08 '18 at 15:58
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    @MichaelKarnerfors: The notability reference in the question doesn't need to be a reliable source of empirical evidence. It just needs to explain what the claim is, and demonstrate that a large number of people believe it. The whole point of the site is that when someone finds a dodgy claim and isn't sure whether it is true, to ask for help finding quality evidence. – Oddthinking Jan 08 '18 at 16:43
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    Note that phosphor is a generic term for "compound that emits light" and it's the used term for the stuff that coats some lamps (or CRT tubes). It's not phosphorous or a phosphorous compound. In fact phosphorous is (confusingly) not used in phosphor. Reference: https://chemistry.stackexchange.com/questions/81915/phospors-and-phosphorus – Sklivvz Jan 08 '18 at 17:18
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    @Oddthinking Well the point is I find no indication here that a large — or even significant — number of people believe the claim that compounds in low energy lights are anti-coagulant. What I find is that this claim is made on that one website (nemesis lonestar org), with **no references at all**, and subsequent claims are only quoting lonestar verbatim. I do not think this is a notable claim. Also I have never heard of **any** substance that is such that if you get any amount of it in a wound, your blood clotting ability disappears or is even significantly affected. –  Jan 09 '18 at 07:47

2 Answers2

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Not in any way that would make it dangerous.

Warfarin and Coumarin, two pharmaeutical compounds that are used for their severe anticoagulant effects, are fluorescent - Warfarin having a peak emission of ~370nm when excited with 320nm light, so not exactly ideal for CFL lighting, additionally, both are organic compounds and as such would not be used in a high-UV environment, like the inside of a CFL, for any length of time. Mineral is the way to go there.

The fluorescent Warfarin is an anticoagulant that is widely known as a rodent poison. Another well known rodent poison was Thallium sulfate (usually just called 'Thallium') - Thallium (not sulfate) also used to be part of CFL phosphors before it got replaced by more benign alternatives... so this might be a source of the myth.

Also, in very old (pre-1950s) fluorescent lamps, Beryllium was present, which is rather nasty, and was credited with adding insult to injury in cuts from lamp-shards. The reports of wounds 'refusing to heal' (for two months!) might also have gotten garbled to 'refuse to stop bleeding'

This 2011 study on glass-fragment removal has a CFL-victim, but reports no special treatment/circumstances.

A pamphlet on work safety from 2008 actually mentions a problem with clotting for cuts by CFL through the phosphor, but does not provide any references for that. It could very well be from the same disinformation source as the 'grassroots campaign' against energy saving lamps that is one of the links in the Q (same timeframe)

A site on lighting mentions it can lead to clotting.

Modern Fluorecent lights contain a mixture of many rare earth metals (REE) because they all phosphoresce vigorously in UV (the red phosphors Y2O3:Eu3+ (YOX), the green phosphors LaPO4:Ce3+,Tb3+ (LAP), (Gd,Mg)B5O12:Ce3+,Tb3+ (CBT), (Ce,Tb)MgAl11O19 (CAT) and the blue phosphors BaMgAl10O17:Eu2+)- looking at the MSDS or toxicity studies on this we see that their salts are often anticoagulant. Still, e.g. Cerium will show (systemic!) anticoagulant effects after injecting 100mg/kg (not like, lethal, just experimentally noticeable). Fluorescent tubes are coated with about 0.7mg/cm² of phosphor, of which a 27% are REE, so about 0.08mg/cm².

Danger from the anticoagulant properties of CFL shards can be ruled out. Having REE particles in higher dosage in/on your body for an extended period of time may be inadvisable, but more along the lines of a rash and bad wound healing.

bukwyrm
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  • Thank you for your research. Yes, that pamphlet doesn't seem to provide any references, other than the Philips one which I can't track down, even from just the filename in `www.nam.lighting.philips.com/us/ecatalog/msds/s08-93005.pdf`, and that site "has been excluded from the Wayback Machine." A couple of other Philips MSDS docs [A](https://www.assets.lighting.philips.com/is/content/PhilipsLighting/12c50d3c15194cb495fda4a300b395f2), [B](https://www.1000bulbs.com/pdf/philips-149021-msds.pdf) make no mention of any danger from their phosphors. (Although the radioisotope Kr85 may be present.) – Andrew Morton Jul 05 '23 at 16:05
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    This seems to veer around to hit a lot of issues that aren't addressing the question. Warfarin being fluorescent has no relevance. Speculation at the cause of the myth should be referenced. That no-one in South Africa was cut by fluorescent bulbs doesn't mean fluorescent bulbs aren't dangerous if someone is cut by them. The pamphlet specifically mentions phosphor which you seem to have overlooked as an agent. – Oddthinking Jul 05 '23 at 17:06
  • @Oddthinking you are right about the utter meaninglessness of the SA paper in regards to the Q. I got carried away. Deleted it. – bukwyrm Jul 05 '23 at 20:23
  • If you cut yourself on shards of glass, **that** is the immediate danger but also one that is easy to avoid. The total amount of exposure to the phosphor is likely to be *extremely* low with a cut (unless you brew up the shards and inject yourself with the liquor). The risk, compared to the damage of any cut is likely unmeasurably small. – matt_black Jul 05 '23 at 20:38
  • @matt_black: That is a perfectly reasonable conjecture. But what is missing here is any evidence. – Oddthinking Jul 06 '23 at 06:41
  • The comments and this answer are going in circles. (1) Broken glass is dangerous. (2) Mercury is dangerous, and we can easily find studies about mercury exposure with broken CFLs. (3) The substance referred to informally as phosphor (which may or may not contain the element Phosphorus) has been notably alleged to make cuts on broken CFL dangerous because of its anticoagulant properties. We are looking for evidence either way on that claim. – Oddthinking Jul 06 '23 at 06:42
  • @Oddthinking Yes, I was making a conjecture. But the *dose* of phosphor is relevant to whether any effect would be a material worry and, given the scenarios described, it is very hard to see how the dose could be large even if there is some anticoagulant effect. Perhaps someone has calculations on the total quantity of phosphorus in a typical tube which could be some plausible exposure rates from a shard. – matt_black Jul 06 '23 at 18:36
  • @matt_black: I am not here to argue about whether your conjecture is right; I am here to argue it is irrelevant and doesn't belong on the site. In the question we have a published article from LightBulbChoice with references. In the comments, we have an Internet random positing their thoughts without evidence. Please go get some evidence first. – Oddthinking Jul 06 '23 at 18:43
  • The most important part of this answer is underplayed. The penultimate paragraph references what materials are used as phosphors, their known properties (including safety) and the amount in a typical tube. But underemphasises the relevance of the *amount*. Also the reference to cerium bein anticoagulant is to ingestion of large doses of *soluble* cerium not to the insoluble oxides used in phosphors. This should be sufficient to establish that "dangerously anticoagulant" is not a thing. – matt_black Jul 07 '23 at 09:04
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    It is also worth noting that some of the references (eg https://www.designlife-cycle.com/fluorescent-lights-lifecycle) that claim safety worries about phosphors *clearly* confuse *phosphor* with *phosphorus* which deeply undermines their concerns (and might be one source for the myths). – matt_black Jul 07 '23 at 09:10
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Material Safety Data Sheets (MSDS) document the known health/exposure risks of hazardous substances. They are legally required to be provided by manufacturers in some circumstances.

We can look at the MSDS documents for CFL lights.

Starting with the one that makes the clearest, strongest statements:

  • ProLume® Eco-Shield® Fluorescent Lamps MSDS

    It explains what the phosphor is, and how much is present:

    The ProLume Eco-Shield product line uses two different phosphor systems. One phosphor system (halophosphate) uses calcium chloro-fluoro-phosphate, with small amounts (less than 1- 2% by weight the phosphor) of antimony and manganese, both of which are tightly bound in the phosphor matrix. The second phosphor system (SP/SPX) uses a mixture of rare earth elements such as lanthanum, and yttrium as either an oxide or as a phosphate, along with a barium/aluminum oxide. These phosphors produce better lamp efficiency and color rendition. The phosphor components may vary slightly depending on the color of the lamp (cool white, warm white, etc.). Normally a 1.5 inch diameter (T12) fluorescent lamp has approximately 1 - 1.25 grams of the phosphor per foot of lamp, resulting in about 4 - 5 grams of the phosphor coating it’s inside length. A 1 inch diameter (T8) lamp has approximately 1.5 - 2 g phosphor coating per lamp.

    It them goes on to talk about health concerns:

    Except for small modifications, the halophosphor is essentially the same material that has been in use in fluorescent lamps for over fifty years. No significant adverse effects, either by ingestion, inhalation, skin contact, or eye implant, were found in a five-year animal study of the original phosphor by the Industrial Hygiene Foundation of the Mellon Institute. Also, there have been no significant adverse effects on humans by any of these routes during the many years of its manufacture or use. The phosphor is somewhat similar to the inert mineral apatites (calcium phosphate-fluorides) which occur in nature. Antimony, manganese, yttrium and barium compounds are characterized by OSHA as hazardous chemicals, as are most inorganic compounds. However, due to their insolubility, relatively low toxicity and small amount present in the phosphor and the lamp, these materials do not present a significant hazard in the event of breakage of the lamp.

    My search for a reference to the original animal study turned up nothing. This is a weakness in this answer.

    I do note that they never use the term "compact" or CFL. I found them sold at Walmart and they are labelled as CFL there, and certainly look compact.

  • TCP's CFL MSDS:

    Again, it talks about the presence of phosphor:

    Phosphor – (nuisance dust) phosphate mix using manganese, rare earth elements such as lanthanum, and yttrium as either an oxide or as a phosphate, along with a barium/aluminum oxide all are tightly bound in the phosphor matrix. These phosphors produce better lamp efficiency and color rendition. The phosphor components may vary slightly depending on the color of the lamp. Some lamps may contain a thin coating of tin oxide inside the glass.

    Under Health Concerns it explains:

    There have been no significant adverse effects on humans by ingestion, inhalation, skin contact, or eye contact. Antimony, manganese, yttrium and tin compounds are characterized by OSHA as hazardous chemicals, however, due to their insolubility, relatively low toxicity and small amount present in the phosphor and lamp, these materials do not present a significant hazard in the event of breakage of the lamp.

  • Philip;s CFL MSDS similarly says there are no "important symptoms and effects" to be concerned about.

  • FEIT Electric's CFL MSDS says:

    Phosphor dust is considered to be physiologically inert and as such, has an OSHA exposure limit of 15 mg/cubic meter for total dust and 5 mg/cubic meter for respirable dust.

    For cuts, it suggests:

    Perform normal first aid procedures

In summary, the manufacturer's legally-required descriptions of the dangers of CFL tubes covers a number of threats (including mercury), but do not mention anti-coagulant properties, and consider the phosphor safe for skin contact in the amounts present.

Oddthinking
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  • The toxicity mentioned in these MSDS only covers cases that would not be relevant in case of laceration or impalement - "ingestion, inhalation, skin contact, or eye implant" would all not neccessarily uncover influence on the coagulation. I concur though that the MSDS would contain mention of such dangers if they were known. – bukwyrm Jul 06 '23 at 21:12