Life expectancy vs Lead exposure?

[bjdhjy888]

Hi,

    I often do hands-on experiments with lead containing PCB, solder paste and soldering lead containing solder. I wash my hands after each experiement. I use a fan with a filter to rid the soldering smoke out of my room and an air quality monitor to display real time air quality data.

    Still, I'm concerned about my health in the long run. Will lead harm my body in the long run? Will I get any chances of developing any heavy metal poisioning problems?

    Or, it's totally safe to work with lead solder, lead solder paste and PCB???

 

[bsfeechannel]

Ask how many on this forum died because of the use of leaded solder.

[Gyro]

You are as safe as it's possible to be in this world. 

Washing your hands, as you do, is the best precaution against lead ingestion by transferring it to food etc.  Normal soldering temperatures are far too low to cause any lead vapour to form.

Your biggest health risk is actually from the flux fumes which can vary from being a respiratory irritant, to triggering asthma attacks if a sufferer, to long term respiratory issues. Stay out of the fumes by using air movement / filtering / extraction and again, you'll be fine.

Ironically, the flux used in lead-free solders is a lot more 'nasty'. It's best to avoid those.

[radiolistener]

Some times ago people used mercury as medicament from different diseases. Also radioactive elements was used for better health

Lead is nothing in comparison with that 

[Old Printer]

As my name implies, I grew  up in an old fashioned print shop. So did my father, uncle and grandfather and assorted cousins. Up until the late 80's we ran hot metal type, Linotype, lead type. We handled lead constantly, cut it with saws, melted it down and recast it time and time again. The previous generations all lived healthy lives and died in their mid to late 80's of natural causes. I am not saying lead is nice stuff, particularly in young children, but based on my experience it is a bit over blown. Trades people know a lot of other trades people, and I know a lot of old printers who spent their lives around lead without health problems.

[Audioguru again]

I have always used a Weller temperature controlled soldering iron. It melts the rosin in solder making no smoke. Some people with poor health might have used a cheapo soldering iron that has no temperature control so it gets way too hot and incinerates the rosin in solder making nasty smoke.

[gildasd]

I´d be far more worried about lead potable water pipes than solder fumes/handling lead using our brains.

[KaneTW]

Don't ingest lead salts or particles and you'll be fine.

[Gyro]

Some times ago people used mercury as medicament from different diseases. Also radioactive elements was used for better health

Lead is nothing in comparison with that 

Lucky you didn't work in Stockport (Cheshire), aka, the hat capital of the UK. In previous centuries, they used Mercury Nitrate to improve the felting process of camel hair. This lead to the 'Mad Hatter' in Alice in Wonderland and the term 'mad as a Hatter'.

Sadly, it was so much more dangerous but less smelly than the previous process using Urine!

[Gyro]

I´d be far more worried about lead potable water pipes than solder fumes/handling lead using our brains.

Yes, there are still an awful lot of Lead supply pipes in use in domestic water feeds (the length between the street main and the house stop-tap) in older houses. Hard water areas are reasonably ok because the inside of the pipe builds up a protective layer of limescale, but in soft water areas this does not happen and quite a lot of lead can leach into the water while it is stationary over night. It's important to run the tap before drinking (assuming showers and other usage haven't already flushed it through).

[soldar]

Ask how many on this forum died because of the use of leaded solder.

I died once. Then I got better.

I have been handling lead pipes, solder, etc since long before there was any conscience that lead was bad for you. I've been told it won't kill you but it will affect the brain and make you retarded. Whenever my wife points out I am doing something retarded I blame all the lead vapors I breathed in the past. If it weren't for that I'd had been like Einstein. As it is I am like a retarded Einstein, bald and fat. Probably all due to the lead I ingested some decades ago.

[ataradov]

If you are doing electronics as a hobby, then really don't worry about lead exposure. It is not going to give you any issues.

I would be more worried about breathing flux fumes, especially from no-clean and active fluxes.

[bob91343]

In high school I played with mercury and it definitely got into my fingers.  I have been soldering with tin-lead alloy for most of my life, including inhaling the fumes, on a regular basis.  I didn't paint much but that stuff used to contain lead.  Not to speak of the toy soldiers, etc.

I don't know if my life expectancy has been threatened but this week I will be 87 and have no obvious symptoms of poisoning from these activities.

Today's world seems very paranoid.  I try to keep it on a common sense level.  I don't eat solder or mercury, primarily because I doubt it tastes good.  A side benefit is that I am not intentionally poisoning myself.

If I die from any of this, I promise to let you all know.

[soldar]

People who need to take care are those who work soldering all day in a production line. That type of thing.

Have a suction fan pulling fumes away.

[dcbrown73]

Use an extraction fan when soldering and wash your hands afterwards working with electronics. 

Things not to do while soldering.

• Eat finger foods
• Bite your nails
• Lick your fingers
• Lick your butt like a dog.  (Not lead, but still gross and will make you sick)

[janoc]

People who need to take care are those who work soldering all day in a production line. That type of thing.

Have a suction fan pulling fumes away.

Flux fumes, not lead. Lead needs somewhere around 800 480 degrees C (EDIT: it was 900 Fahrenheit I have remembered) to form toxic fumes, if I recall correctly. Normal soldering temperatures are nowhere near that.

If you search the forum, I have posted a link to a study in the past that did evaluate the effects of factory working populating boards every day and working with wave soldering machines and similar - the lead level in their bodies was pretty much the same as everyone else's (i.e. people that didn't work there). The risk was minimal.

Lead is a problem if you ingest it (e.g. lead shavings/dust - some people love to hold the solder wire in their mouth!). That is mitigated by basic hygiene - washing hands, not eating on your bench, etc. Or when it accumulates in the environment where it could leach into water or contaminate soil (e.g. from a landfill full of discarded electronics). That's why RoHS exists.

However, the risk for someone doing electronics soldering, even on a factory production line, is very low. Leaded solder has been used for electronics for almost 100 years and no issues with lead poisoning are known - the concentrations as just too tiny to have an effect. Leaded paint, water pipes or leaded gasoline that has been used for decades are much worse.

[ejeffrey]

Leaded paint, water pipes or leaded gasoline that has been used for decades are much worse.

Right.  These all have well known ingestion mechanisms.  Lead paint abrades and released dust or is chewed on by children.  Lead pipes are dissolve into water flowing through them. leaded gasoline is released into the air when burned or leaches into ground water when underground tanks leak (which they always do).  Likewise I would avoid anything that requires cutting, machining, or filing lead which would release lead dust.

Soldering isn't major problem for the operator as long as the aforementioned hygiene procedures are followed. The hazard from lead solder comes when the products are disposed of, either by landfill, shredding recycling, or incineration which all cause their own risks.

[james_s]

Leaded gasoline was probably the worst of all by a wide margin. It was atomized and spread all over the planet, during the heyday of leaded gas it was inescapable.

[Gyro]

Leaded gasoline was probably the worst of all by a wide margin. It was atomized and spread all over the planet, during the heyday of leaded gas it was inescapable.

From the man who also brought us CFCs! Sometimes you just can't catch a break.

[Mr. Scram]

Just bear in mind that children are especially susceptible to lead ingestion and may suffer irreversible developmental issues. Unless you lick your fingers after soldering you'll probably be fine but keep it away from children. Also note that while washing your hands with water and soap to remove lead is effective it isn't quite perfect.

[John B]

I always use disposable gloves. When cleaning out the brass wool, there's a lot of fine lead, almost powdered. I would imagine that poses the greatest risk, as it puts a lot of particles in the air, and they would dissolve the easiest.

[Mr. Scram]

I always use disposable gloves. When cleaning out the brass wool, there's a lot of fine lead, almost powdered. I would imagine that poses the greatest risk, as it puts a lot of particles in the air, and they would dissolve the easiest.

Gloves may very well be an ESD risk but I suppose that could be mitigated.

[themadhippy]

Drink plenty of milk.One of my first jobs was in an  oxide manufacturers , all the staff on the lead oxide plant were issued with a pint of milk a day.

[Electro Detective]

cheap fan for the fumes, extract or push away mode, anything is better than breathing the crap in,

cheap thin glove to handle the solder, the other hand can be without, to better handle the soddering/soldering/sardurring iron (pick one  )
and less fiddly parts placement etc.

cheap white mouth-nose protector with elastic thingie,

cheap clear or mild diopter magnifying glasses to see better > and catch any hot spatter and flying molten lead balls
before your eyes do. 

Maybe $20 all up ? cheaper than life insurance that you won't collect, hospital, lung machine hire, earlier funeral,

and worst of all, not being able to solder stuff anymore.   


FWIW: if you think lead solder may be a problem, welders will giggle    and tell you what real problems are   

[Nominal Animal]

As others have well said, lead is only dangerous if ingested or inhaled in vapour form.

As a lay person, it is difficult to get a good intuitive grasp of the actual risks of different materials.
For example, when one talks about uranium, "radiation!" is what pops into peoples minds, immediately.  Yet, uranium is just like lead in that it is a heavy metal that is chemically toxic to animal life, including humans.  Over 99% of uranium in nature is ²³⁸U.  Although radioactive (half-life is four and a half billion years), it is its chemical toxicity that is deadly, just like lead and mercury.  In fact, the dose that is 50% likely to kill you via radiation when ingested, is about 2x to 4x the amount that has already killed you due to its chemical toxicity.  So, unless you intend to wear it like clothes every day for decades, you can forget about the radiation when talking about ²³⁸U; it is its chemical toxicity that will kill you before you need to worry about any effects from its radiation.  And, exactly like with lead and mercury, it is in its fine particulate or vapour form that is the deadliest.  (As welders will tell you, metal vapours/fumes are deadly anyway.)
Uranium is actually even worse, because when vaporized, it reforms into tiny little particulates that may be even more dangerous (by mass, chemically) than the vapour, because of how they are better retained by biological organisms, causing even more damage.

Which makes claims about depleted uranium weaponry being safe utterly ridiculous, by the way.  They're worse than dum-dum bullets, with a droplet of mercury encased in the slug, as the resulting tiny little particulates after hitting any target remain chemically dangerous for decades.

(Your depressing fact for the week brought to you by Nominal Animal.  You're welcome.  I'm off to eat some 50-50 solder, just to see how it tastes.)

[Alex Eisenhut]

Maybe if you make a smoothie out of the boards and drink one every day.

Ask yourself this.

People have been using stuff like this

for decades. There would have been something happening by now?

[bjdhjy888]

Normal soldering temperatures are far too low to cause any lead vapour to form.

https://en.wikipedia.org/wiki/Lead

I just looked up the boiling point of lead on Wikipedia, where it says it's 1749 °C. Does this mean that we can only inhale lead or absorb lead through our skin when our soldering iron's tip reaches a temperature of 1749 °C?
If yes, then I feel super safe now..
 

[tautech]

Maybe if you make a smoothie out of the boards and drink one every day.

Ask yourself this.

People have been using stuff like this
(Attachment Link)
for decades. There would have been something happening by now?

Yep we used to carry them around in our mouth before we knew better. 

[james_s]

Leaded gasoline was probably the worst of all by a wide margin. It was atomized and spread all over the planet, during the heyday of leaded gas it was inescapable.

From the man who also brought us CFCs! Sometimes you just can't catch a break.

To their credit, CFCs are relatively nontoxic, nonflammable and generally inert substances. Nobody realized they would break down the ozone layer, that could have really been a disaster without modern science to detect it and determine the cause.

[maginnovision]

I worked in electronics manufacturing for years using leaded processes. Never got sick or had problems and I'm an asthmatic. Only time I took precautions was cleaning dross from the wave solder machine. I'd wear a mask and gloves(mostly due to the heat). Even if you're just using a soldering iron and a fan you'll be fine. If you didn't use a fan I'd just recommend taking a break before you get a sore throat, drinking water at regular intervals, and taking a shower at the end of the day(with lots of steam) to help cough up anything you managed to get in your lungs.

[Mr. Scram]

I worked in electronics manufacturing for years using leaded processes. Never got sick or had problems and I'm an asthmatic. Only time I took precautions was cleaning dross from the wave solder machine. I'd wear a mask and gloves(mostly due to the heat). Even if you're just using a soldering iron and a fan you'll be fine. If you didn't use a fan I'd just recommend taking a break before you get a sore throat, drinking water at regular intervals, and taking a shower at the end of the day(with lots of steam) to help cough up anything you managed to get in your lungs.

What's being asthmatic got to do with lead poisoning?

[maginnovision]

Nothing it has to do with irritation from flux fumes.

[SkyMaster]

According to Thomas Midgley, lead is inoffensive.

Thomas Midgley was an engineer. He was then probably right.

https://en.wikipedia.org/wiki/Thomas_Midgley_Jr.


Wait, he also invented Freon...


 

[Nominal Animal]

You don't want to eat and drink from lead (or uranium) platters and goblets every day for years, but doing it once hurts you less than breathing in in any densely populated city.

If you do not have open wounds or sores, handling heavy metals like lead or mercury is safe.  Just wash your hands afterwards, so you do not end up ingesting them.
(If you do have wounds or sores, it depends on the material structure.  Usually it does not matter.  The risk, really, is getting some lodged in the wound, so your immune system tries to slowly digest it.  You wouldn't want to deal with heavy metal powders with your bare hands, if you have cuts in your hands.  Just use gloves then.)

Welding and soldering generates fumes.  Welding generates metal vapor (zinc vapor being particularly nasty) and small metal particulates, and both welding and soldering vaporizes some of the flux.  These are most chemically active when hot, so you don't want to breath them in fresh.  If the small particulates are still hot when they get in your lungs, they can embed themselves in the tissues, and since there is a lot of blood flow there, it is not far off from getting them directly in your bloodstream.  So that's bad.  Venting the fumes cools them down, making them much, much less chemically active and thus much less dangerous, and mixing them to the ambient outside air reduces their density to safe levels.  The fumes are much more dangerous in closed spaces: that's why you should always weld outside or a special room with fume extraction and/or air filtration.

If say a factory or a hack lab has welding or soldering stations, they should have an air filter unit.  However, this too is a balance: making such air filters takes resources and generates pollution, so such an air filter really should be used enough to warrant itself, or it will be a net loss for the environment.

Environmental risk management is something where you need both rational thinking, and a wide range of facts to rely on.  (For example, like ²³⁸U being a heavy metal and dangerous due to its chemistry, like lead and mercury, and not because it is radioactive.)
It truly is pity that leaded solder is considered dangerous, as the amounts used are minuscule compared to other industries, and the way they are used means the lead is in environmentally pretty safe alloys.  The chemically harsher fluxes needed with non-leaded solders probably negates any benefits anyway.

Anyway, the small bit of 60/40 solder I just ate, didn't taste of anything.  Explains why the Romans used lead in their dinnerware.  Stainless steel has much more of a "metallic" taste.  If I get sick, it would be because of the flux in it.  I won't, though.

[janoc]

I always use disposable gloves. When cleaning out the brass wool, there's a lot of fine lead, almost powdered. I would imagine that poses the greatest risk, as it puts a lot of particles in the air, and they would dissolve the easiest.

Lead really doesn't dissolve easily, not even in acids or strong bases. So no need to panic over that - you most likely don't have anything on or near the bench that could cause it to dissolve in a meaningful time frame. If you put that lead somewhere into a landfill and let it sit in an acid rain or leach into water for years, that would be a different matter.

And those shavings that you clean out of your tip cleaning wool are way too large and heavy to fly far by air (assuming you are not waving the wool around). Those particles would need to be order of magnitude or two smaller to be a meaningful hazard.

Just bear in mind that children are especially susceptible to lead ingestion and may suffer irreversible developmental issues. Unless you lick your fingers after soldering you'll probably be fine but keep it away from children. Also note that while washing your hands with water and soap to remove lead is effective it isn't quite perfect.

If you are afraid that small kids could put it in their mouth and such - if the kids can get to your solder, they most likely can get also to the hot iron or sharp tools on your desk. I would consider that a much bigger issue than a kid licking a solder wire once or twice or touching the wire and then licking their fingers. You really don't die or turn into a babbling drooling vegetable from a tiny exposure like that. Unless that kid is doing that every day for a while, they will likely be fine.

Also, if someone is worried about lead poisoning from a leaded solder - we have lead-free solder too 

Normal soldering temperatures are far too low to cause any lead vapour to form.

https://en.wikipedia.org/wiki/Lead

I just looked up the boiling point of lead on Wikipedia, where it says it's 1749 °C. Does this mean that we can only inhale lead or absorb lead through our skin when our soldering iron's tip reaches a temperature of 1749 °C?
If yes, then I feel super safe now..
 

Boiling point of a substance has literally zero to do with vapor forming. Water also doesn't start to evaporate only once it reaches the boiling temperature! Boiling point is only the temperature when the substance is evaporating from the entire volume (that's what produces the bubbles) and not only the surface.

Vapors can form even when the matter is still solid (sublimation - even solid lead sublimates under certain conditions) or liquid but below the boiling point.

(Pure) lead melts at 327°C and starts releasing fumes at 480°C or so. Common soldering (especially given that we use lead-tin alloys that melt at even lower temperatures than this) has no way to reach that unless you are using a flame thrower to solder.

[janoc]

cheap white mouth-nose protector with elastic thingie,

That will literally do nothing apart from providing you with the feel-good reassurance. Those protectors are only against dust, they don't protect against gases (e.g. flux, lead or paint fumes). Even for dust they aren't great - e.g. almost useless against FR4 or similarly sized fine dust. Those things are really for woodworkers, construction workers demolishing walls and such only.

If you want to protect yourself against fine dust, you need a proper respirator and if you wanted to protect yourself against gases, then you would need a gas mask with a filter matched to the toxins you want to keep out.

[Mr. Scram]

Lead really doesn't dissolve easily, not even in acids or strong bases. So no need to panic over that - you most likely don't have anything on or near the bench that could cause it to dissolve in a meaningful time frame. If you put that lead somewhere into a landfill and let it sit in an acid rain or leach into water for years, that would be a different matter.

And those shavings that you clean out of your tip cleaning wool are way too large and heavy to fly far by air (assuming you are not waving the wool around). Those particles would need to be order of magnitude or two smaller to be a meaningful hazard.

If you are afraid that small kids could put it in their mouth and such - if the kids can get to your solder, they most likely can get also to the hot iron or sharp tools on your desk. I would consider that a much bigger issue than a kid licking a solder wire once or twice or touching the wire and then licking their fingers. You really don't die or turn into a babbling drooling vegetable from a tiny exposure like that. Unless that kid is doing that every day for a while, they will likely be fine.

Also, if someone is worried about lead poisoning from a leaded solder - we have lead-free solder too 

Boiling point of a substance has literally zero to do with vapor forming. Water also doesn't start to evaporate only once it reaches the boiling temperature! Boiling point is only the temperature when the substance is evaporating from the entire volume (that's what produces the bubbles) and not only the surface.

Vapors can form even when the matter is still solid (sublimation - even solid lead sublimates under certain conditions) or liquid but below the boiling point.

(Pure) lead melts at 327°C and starts releasing fumes at 480°C or so. Common soldering (especially given that we use lead-tin alloys that melt at even lower temperatures than this) has no way to reach that unless you are using a flame thrower to solder.

It's not about licking a roll of solder, it's about ingesting particulates like the solder balls that tend to form. This represents a relevant amount of lead although a single isolated exposure is unlikely to do a lot of long term harm. Particulates being under the desk or spread throughout the house as they cling to soles can be a concern.

[janoc]

It's not about licking a roll of solder, it's about ingesting particulates like the solder balls that tend to form. This represents a relevant amount of lead although a single isolated exposure is unlikely to do a lot of long term harm. Particulates being under the desk or spread throughout the house as they cling to soles can be a concern.

Hum, clean your workshop periodically and don't fling solder all over the place in the first place? Those solder balls tend to be pretty macroscopic too. I can understand bits of solder on the bench but if you are worried about them being spread by soles all over the house it sounds like a major cleanup is in order. I solder quite a bit and for some reason don't have solder balls on the floor or in the carpet.

And teach your kids to not put whatever crap they find in the mouth. Frankly, in an average household there are much worse and immediately toxic things I would be worried about a child putting in their mouth than solder particulates on the floor.

But again, if you are worried about the kids, lead-free solder does exist ...

[Mr. Scram]

Hum, clean your workshop periodically and don't fling solder all over the place in the first place? Those solder balls tend to be pretty macroscopic too. I can understand bits of solder on the bench but if you are worried about them being spread by soles all over the house it sounds like a major cleanup is in order. I solder quite a bit and for some reason don't have solder balls on the floor or in the carpet.

And teach your kids to not put whatever crap they find in the mouth. Frankly, in an average household there are much worse and immediately toxic things I would be worried about a child putting in their mouth than solder particulates on the floor.

But again, if you are worried about the kids, lead-free solder does exist ...

We can disparage the risk all day long but it's an avenue of exposure that should be given some thought given the susceptibility of children. Though lead-free solder doesn't exist just to protect the children.

[dom0]

Personally I don't usually bother with the fume extractor for small stuff unless I am working with verowire, which releases rather toxic fumes when you burn the insulating PU lacquer off. I am one of those guys who inhales before soldering and blows at the rosin smoke (it's automated). I use eutectic lead solder with a mild, modified rosin core for most things. (F-SW-31/1.1.1/ROL0).

My fume extractor goes directly out the window, making it my neighbours problem. I wouldn't put too much trust into those little "PC fan with activated carbon mat" fume extractors.

[soldar]

https://nypost.com/2019/08/19/lead-scrubbed-from-paris-streets-as-notre-dame-work-resumes/

PARIS — Specialists shoring up fire-damaged Notre Dame Cathedral returned Monday to the Paris site for the first time in nearly a month, this time wearing disposable suits and other protective gear after a delay prompted by fears of lead contamination.

Meanwhile, cleanup teams swept, sprayed and vacuumed neighboring streets Monday to scrub away any lead left over from the April blaze that destroyed Notre Dame’s roof and toppled its spire. Toxic dust spewed into the air as hundreds of tons of lead melted in the fire.

At the cathedral itself, activity resumed Monday under strict new lead protection measures for the stonemasons, cleanup workers and scientists working on the monument, according to the Culture Ministry. They include throwaway full-body clothing, obligatory showers and a new decontamination zone to ensure that no one tracks pollution outside the site.

[dom0]

When stuff burns everything gets turned into fine and ultra-fine particulates. Same with lead. They are worried about dust and particulates contaminated with leaded compounds.

[Old Printer]

https://nypost.com/2019/08/19/lead-scrubbed-from-paris-streets-as-notre-dame-work-resumes/

PARIS — Specialists shoring up fire-damaged Notre Dame Cathedral returned Monday to the Paris site for the first time in nearly a month, this time wearing disposable suits and other protective gear after a delay prompted by fears of lead contamination.

Meanwhile, cleanup teams swept, sprayed and vacuumed neighboring streets Monday to scrub away any lead left over from the April blaze that destroyed Notre Dame’s roof and toppled its spire. Toxic dust spewed into the air as hundreds of tons of lead melted in the fire.

At the cathedral itself, activity resumed Monday under strict new lead protection measures for the stonemasons, cleanup workers and scientists working on the monument, according to the Culture Ministry. They include throwaway full-body clothing, obligatory showers and a new decontamination zone to ensure that no one tracks pollution outside the site.

Industries will appear where ever there is money.

Besides working with lead most of my life, I spent a good number of years competing in indoor small bore rifle matches. In those days most indoor ranges did not have air scrubbing systems. My doctor suggested having my blood lead level checked at my yearly physical. As I recall it was a pretty minimal expense, and my results were never out of the normal range. So if anyone is concerned about their exposure, it's not hard or expensive to get it checked at your next physical. Lead in developing brains can have serious long term effects, but in healthy adults treating it as uranium is fear mongering IMO.

[bjdhjy888]

I felt super safe when I was reading you guys' replies.

Then....when I was soldering my STM32 a moment ago, my air quaility meter read:
PM 2.5   100+ ug/sq meters
PM 10    300+ ug/sq meters

OMG!

I tried to read the numbers with my door closed and open, while my fan was working, blowing fumes out of my window. Either way, the numbers were all above 100+, up to 300+
I used lead solder and solder paste.

The readings dropped to 63 and 109 respectively, after 30 minutes.

 

[janoc]

We can disparage the risk all day long but it's an avenue of exposure that should be given some thought given the susceptibility of children. Though lead-free solder doesn't exist just to protect the children.

Christ ... Do you know that even drinking water can kill you? (no kidding). Or you could get hit by a meteorite.  I guess we better don't drink and stay indoors 24/7 then.

It is not about disparaging anything but about evaluating the consequences vs real exposure risks instead of falling for hysterical  alarmist bullshit.

[janoc]

https://nypost.com/2019/08/19/lead-scrubbed-from-paris-streets-as-notre-dame-work-resumes/

PARIS — Specialists shoring up fire-damaged Notre Dame Cathedral returned Monday to the Paris site for the first time in nearly a month, this time wearing disposable suits and other protective gear after a delay prompted by fears of lead contamination.

Meanwhile, cleanup teams swept, sprayed and vacuumed neighboring streets Monday to scrub away any lead left over from the April blaze that destroyed Notre Dame’s roof and toppled its spire. Toxic dust spewed into the air as hundreds of tons of lead melted in the fire.

At the cathedral itself, activity resumed Monday under strict new lead protection measures for the stonemasons, cleanup workers and scientists working on the monument, according to the Culture Ministry. They include throwaway full-body clothing, obligatory showers and a new decontamination zone to ensure that no one tracks pollution outside the site.

How is that relevant to this topic? Nobody is disputing that lead is toxic.

You do realize that there are a few hundreds of tons of lead melted there and toxic dust from the fire, right? None of which you are likely to have in your workshop.

[Mr. Scram]

Christ ... Do you know that even drinking water can kill you? (no kidding). Or you could get hit by a meteorite.  I guess we better don't drink and stay indoors 24/7 then.

It is not about disparaging anything but about evaluating the consequences vs real exposure risks instead of falling for hysterical  alarmist bullshit.

I'm sure the French government is spending millions to clean up due to "alarmist bullshit" instead of actual risks? Actual research shows lead intake is cumulative and definitely harmful at blood levels of 10 µg/dL. It could be worse though. "There is no known safe blood lead concentration. But it is known that, as lead exposure increases, the range and severity of symptoms and effects also increases. Even blood lead concentrations as low as 5 µg/dL, once thought to be a “safe level”, may be associated with decreased intelligence in children, behavioural difficulties, and learning problems." You won't keel over instantly and the biggest risk is definitely associated with children but it is a veritable toxin and should be handled with consideration.

[Nominal Animal]

• Lead salts are most dangerous, because they are very efficiently absorbed into the body.
• When ingested, adult bodies absorb only about 1% of pure lead, the rest is excreted in a few weeks.
• When ingested, child bodies absorb about 33% of pure lead.
• Nanoparticles and very fine dust easily lodges in human lungs.
  The smaller a particle has, the larger surface-to-volume ratio it has.  Because the surface is where chemical reactions occur, the same weight or volume of nanoparticles causes an order of magnitude more chemical reactions than a single nonporous chunk.  This is how car catalysers work.
  Because of their reactivity, nanoparticles can easily embed themselves in lung tissue, and even enter the blood stream.
• Adult human bodies contain about 0.1g of lead, total, on average.

I recently ingested a cubic millimeter of 60-40 lead alloy, containing about 0.7 mg of lead.  If this was pure lead, my body would retain about 1% of it, or about 1 µg.  This increases the amount of lead in my body by about 0.001%.  Let's say I repeat this every day for a year, accumulating about 400 µg = 0.4 mg of lead into my body.  That is still only a 0.4% increase in the amount of lead in my body.  I could do this for the rest of my life, and even if I were to live to be 100 years old, I'd only increase the lead content in my body by about 25%.  It is not enough to raise the coroners eyebrow: where you live and what kind of air you breath, makes a bigger difference.

So, worrying about millimeter-sized lead or lead-alloy spherules only matters if you have kids.

Statistically, if we were to increase the lead load by 25% for an entire population, we'd likely see some negative health effects.  This is why banning lead paint is a good idea, especially for toys.  (The lead in lead paint is in suspension, and can be in basically nanoparticle form.  Same for lead additives in fuels.  Lead salts are even worse, because almost all of them get absorbed into the body when ingested.)

But, as you can see from the above calculation, the amount of lead in solder and how it is in a form so unlikely to get into human bodies, makes leaded/unleaded solder discussion completely wacky.  Electronics already contain much worse chemicals making it necessary to dispose of them properly (to avoid negative health effects on the human population), and leaded/unleaded solder has an utterly insignificant effect there.

[james_s]

I felt super safe when I was reading you guys' replies.

Then....when I was soldering my STM32 a moment ago, my air quaility meter read:
PM 2.5   100+ ug/sq meters
PM 10    300+ ug/sq meters

OMG!

I tried to read the numbers with my door closed and open, while my fan was working, blowing fumes out of my window. Either way, the numbers were all above 100+, up to 300+
I used lead solder and solder paste.

The readings dropped to 63 and 109 respectively, after 30 minutes.

 

What exactly does your air quality meter measure? These are not typically precision devices, the one built into a room air filter thing we have pegs every time I fire up the gas oven in the kitchen or use a squirt of canned air across the room. It only measures certain characteristics, it doesn't really tell you with any certainty what it has detected or whether it is harmful.

[Mr. Scram]

• Lead salts are most dangerous, because they are very efficiently absorbed into the body.
• When ingested, adult bodies absorb only about 1% of pure lead, the rest is excreted in a few weeks.
• When ingested, child bodies absorb about 33% of pure lead.
• Nanoparticles and very fine dust easily lodges in human lungs.
  The smaller a particle has, the larger surface-to-volume ratio it has.  Because the surface is where chemical reactions occur, the same weight or volume of nanoparticles causes an order of magnitude more chemical reactions than a single nonporous chunk.  This is how car catalysers work.
  Because of their reactivity, nanoparticles can easily embed themselves in lung tissue, and even enter the blood stream.
• Adult human bodies contain about 0.1g of lead, total, on average.

I recently ingested a cubic millimeter of 60-40 lead alloy, containing about 0.7 mg of lead.  If this was pure lead, my body would retain about 1% of it, or about 1 µg.  This increases the amount of lead in my body by about 0.001%.  Let's say I repeat this every day for a year, accumulating about 400 µg = 0.4 mg of lead into my body.  That is still only a 0.4% increase in the amount of lead in my body.  I could do this for the rest of my life, and even if I were to live to be 100 years old, I'd only increase the lead content in my body by about 25%.  It is not enough to raise the coroners eyebrow: where you live and what kind of air you breath, makes a bigger difference.

So, worrying about millimeter-sized lead or lead-alloy spherules only matters if you have kids.

Statistically, if we were to increase the lead load by 25% for an entire population, we'd likely see some negative health effects.  This is why banning lead paint is a good idea, especially for toys.  (The lead in lead paint is in suspension, and can be in basically nanoparticle form.  Same for lead additives in fuels.  Lead salts are even worse, because almost all of them get absorbed into the body when ingested.)

But, as you can see from the above calculation, the amount of lead in solder and how it is in a form so unlikely to get into human bodies, makes leaded/unleaded solder discussion completely wacky.  Electronics already contain much worse chemicals making it necessary to dispose of them properly (to avoid negative health effects on the human population), and leaded/unleaded solder has an utterly insignificant effect there.

Where did you grab those numbers on lead absorption?

[Nominal Animal]

Wikipedia, here and here.

[bsfeechannel]

I died once. Then I got better.

Well, technically, all cells of your body will be naturally replaced every decade or so.

[janoc]

I'm sure the French government is spending millions to clean up due to "alarmist bullshit" instead of actual risks?

Are you seriously comparing exposure of the workers in the middle of hundreds of tons of lead from the cathedral roof that has both melted down, pulverized and evaporated in the heat of that huge fire to an exposure that you could get by soldering?

Really? 

Actual research shows lead intake is cumulative and definitely harmful at blood levels of 10 µg/dL. It could be worse though. "There is no known safe blood lead concentration. But it is known that, as lead exposure increases, the range and severity of symptoms and effects also increases. Even blood lead concentrations as low as 5 µg/dL, once thought to be a “safe level”, may be associated with decreased intelligence in children, behavioural difficulties, and learning problems." You won't keel over instantly and the biggest risk is definitely associated with children but it is a veritable toxin and should be handled with consideration.

Nobody is disputing toxicity of lead. But there is a big difference between touching lead and having it in your blood!

Here is some actually relevant reading material:

https://apps.dtic.mil/dtic/tr/fulltext/u2/a145663.pdf (OSHA study of soldering in military environment - "No significant inhalation hazard, low order ingestion hazard" (some were holding the solder in their mouths).

"Occupational Lead Exposure Of Soldering Workers  In An Electronic Factory" - conclusion ("In  conclusion,  since  the  biological  indicators  showed  normal  values,  the  electronic  circuit  board  soldering workers, are not at high risk of exposure to occupational lead.")

https://s3.amazonaws.com/academia.edu.documents/36286554/vol1no2271204.pdf?response-content-disposition=inline%3B%20filename%3DOccupational_Heat_Exposure_of_Workers_in.pdf&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAIWOWYYGZ2Y53UL3A%2F20190821%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20190821T143158Z&X-Amz-Expires=3600&X-Amz-SignedHeaders=host&X-Amz-Signature=4e095684a2168761addbc3525ece09b4ead79b1a37fedd5a27ca0f0610d88602#page=9

And if you are worried about kids, then either don't use leaded solder or keep them away from your work area (which is likely a prudent idea anyway, given the other dangers from the tools and electricity present there).

[janoc]

Wikipedia, here and here.

And your point is? Nobody is disputing that lead is toxic.

[james_s]

Wikipedia, here and here.

And your point is? Nobody is disputing that lead is toxic.

I think his point is that somebody asked where he got the information about absorption so he answered the question.

[janoc]

Wikipedia, here and here.

And your point is? Nobody is disputing that lead is toxic.

I think his point is that somebody asked where he got the information about absorption so he answered the question.

Ah sorry, I got a bit worked up by Scram's post and missed that context. It looked just like another random "lead is bad" (which everyone knows and nobody argues with) post to me.

[Mr. Scram]

Ah sorry, I got a bit worked up by Scram's post and missed that context. It looked just like another random "lead is bad" (which everyone knows and nobody argues with) post to me.

Are you sure you haven't been exposed to lead more than you should? Aggression and diminished mental acuity are side effects of lead poisoning.  All joking aside the subject seems relevant to almost everyone here. I'd prefer to have a civil discussion based on facts presented as chances are we'd learn something. It's really not worth getting worked up about anyway.

[Mr. Scram]

Are you seriously comparing exposure of the workers in the middle of hundreds of tons of lead from the cathedral roof that has both melted down, pulverized and evaporated in the heat of that huge fire to an exposure that you could get by soldering?

Really? 

Nobody is disputing toxicity of lead. But there is a big difference between touching lead and having it in your blood!

Here is some actually relevant reading material:

https://apps.dtic.mil/dtic/tr/fulltext/u2/a145663.pdf (OSHA study of soldering in military environment - "No significant inhalation hazard, low order ingestion hazard" (some were holding the solder in their mouths).

"Occupational Lead Exposure Of Soldering Workers  In An Electronic Factory" - conclusion ("In  conclusion,  since  the  biological  indicators  showed  normal  values,  the  electronic  circuit  board  soldering workers, are not at high risk of exposure to occupational lead.")

https://s3.amazonaws.com/academia.edu.documents/36286554/vol1no2271204.pdf?response-content-disposition=inline%3B%20filename%3DOccupational_Heat_Exposure_of_Workers_in.pdf&X-Amz-Algorithm=AWS4-HMAC-SHA256&X-Amz-Credential=AKIAIWOWYYGZ2Y53UL3A%2F20190821%2Fus-east-1%2Fs3%2Faws4_request&X-Amz-Date=20190821T143158Z&X-Amz-Expires=3600&X-Amz-SignedHeaders=host&X-Amz-Signature=4e095684a2168761addbc3525ece09b4ead79b1a37fedd5a27ca0f0610d88602#page=9

And if you are worried about kids, then either don't use leaded solder or keep them away from your work area (which is likely a prudent idea anyway, given the other dangers from the tools and electricity present there).

Those hundreds of tons are spread around a large area. Keeping children away from tools is a good idea but doesn't preclude the spread of lead outside of the direct soldering area.

[Mr. Scram]

Wikipedia, here and here.

Thanks. I think those numbers should be taken as 1% ultimately being retained rather than 1% being absorbed by your gastronomic system. Meanwhile the other 99% seem to be roaming your body until excreted a few weeks later.

[Nominal Animal]

All joking aside the subject seems relevant to almost everyone here. I'd prefer to have a civil discussion based on facts presented as chances are we'd learn something. It's really not worth getting worked up about anyway.

Absolutely; and not just that, but seeing the basis of others viewpoints gives a much better overall picture.

Life is not a game.  There are no "points" awarded on being right or wrong.  What matters, is that you mentally model the reality around you in ways that allow you to act efficiently in the world.  I prefer rational-analytic thinking, but many moderate religions can also provide such a framework.  For example, the prevalence of trichinella in pork (causing trichinosis in humans, which is pretty horrible) well explains why some consider it "tainted".  For us rational-analytical agnostics, knowing stuff like that makes it much easier to cooperate with religious people, as there is a good idea (that was very pertinent once) behind the edicts.  (Just remember that most humans are not smart or rational, and cannot understand the reasons why some things are bad or to be avoided.  They need the rules.)

For lead, it may be hard for laypeople to understand that lead absorbs into growing bodies at 33 times the rate it does for adults, and what that means when considering the use of lead compounds.  Considering the effects of lead, violence in particular (it has been suggested that the reduction in lead additives in gasoline is a significant reason why violence in western societies has been clearly decreasing in similar fashion -- but correlation is not causation), it is definitely better to be too cautious than cavalier about lead.

It just happens that leaded solder is a clear exception.  Where it is used, there is already a lot of other metals, necessitating proper disposal anyway.  It is in an alloy form, making it quite safe for adults.  (Actually, I tried (a bit, I'm lazy) to find the alloy absorption rates for children, as I think they are much smaller than for lead, but couldn't find any.)  Using non-leaded solder involves the use of harsher chemicals, and I'm not sure if they have solved the issues regarding tin whiskers and such in the long term yet.

So, it is an interesting topic, and complex enough to discuss.

[Nominal Animal]

Meanwhile the other 99% seem to be roaming your body until excreted a few weeks later.

If you consider exactly how heavy metals cause cellular damage, that may be much less dangerous than you think.

Anyway, the small slug of leaded solder I ate has tiny surface area compared to its mass, and does not really dissolve in hydrochloric acid (stomach acid).  It is basically the safest form of lead to ingest.  I believe it has basically passed unchanged from my system, with only some of the surface alloy possibly passing through to my blood; insignificant amounts to worry about -- and only a fraction of the already minuscule amounts I calculated before.  But very interesting to consider in a rational fashion, definitely!

If a kid had eaten a solder ball, I do not think it would warrant using emetics, overall.  A few, or a length of solder, might.  Using emetics, there is always the risk of getting stomach acids in the lungs, which definitely causes irreparable damage.  I am not sure if charcoal would make any difference.  Milk might suffice.

I believe the calculations in my earlier post would match the worst case scenario, eating lead dust.  In macroscopic form, only the surface layers are really subject to dissolving (in stomach acid) and passing to the blood stream.  Also, diet affects lead absorption a lot, and indeed milk is an effective protection against lead being absorbed.

[Mr. Scram]

If you consider exactly how heavy metals cause cellular damage, that may be much less dangerous than you think.

Anyway, the small slug of leaded solder I ate has tiny surface area compared to its mass, and does not really dissolve in hydrochloric acid (stomach acid).  It is basically the safest form of lead to ingest.  I believe it has basically passed unchanged from my system, with only some of the surface alloy possibly passing through to my blood; insignificant amounts to worry about -- and only a fraction of the already minuscule amounts I calculated before.  But very interesting to consider in a rational fashion, definitely!

If a kid had eaten a solder ball, I do not think it would warrant using emetics, overall.  A few, or a length of solder, might.  Using emetics, there is always the risk of getting stomach acids in the lungs, which definitely causes irreparable damage.  I am not sure if charcoal would make any difference.  Milk might suffice.

I believe the calculations in my earlier post would match the worst case scenario, eating lead dust.  In macroscopic form, only the surface layers are really subject to dissolving (in stomach acid) and passing to the blood stream.  Also, diet affects lead absorption a lot, and indeed milk is an effective protection against lead being absorbed.

I've tried finding actual absorption rates of alloyed or pure lead but pretty much all materials seem to focus on more commonly found environmental hazards like lead paints. The lead acetate in paint is presented in thin neat flakes with a huge surface area and is water soluble. Worse still it's sweet so children eat it as a candy instead of just occasionally. Combined with the large lead absorption rate in children it's an accident waiting to happen.

[bjdhjy888]

Though I believe you guy's confident comments on safety for soldering, I seriously think I need to get one of these:

[Nominal Animal]

bjdhjy888: When you solder, there are fumes from the flux too; and if you are anything like me, there's always some piece of plastic melting or burning (from wires or whatever plastic happened to lay on the bench too close to the iron tip when I was looking at some detail).

These fumes are nasty.  You do not want to breathe those fumes.  We just recommend ventilation over a mask, that's all. 

[maginnovision]

bjdhjy888: When you solder, there are fumes from the flux too; and if you are anything like me, there's always some piece of plastic melting or burning (from wires or whatever plastic happened to lay on the bench too close to the iron tip when I was looking at some detail).

These fumes are nasty.  You do not want to breathe those fumes.  We just recommend ventilation over a mask, that's all. 

For some reason I always manage to tag my microscope cover. 

[djacobow]

When I was a little boy fishing with my dad, I more than once put a lead weight in my mouth and chewed it. And we always used our teeth to close the weights on the line, anyway.

So I think the damage is done for me. :-)

That said, there are some fascinating studies that suggest that leaded gasoline seriously poisoned multiple generations of humanity. Some link the drop in crime in the 00's to the banning of leaded gas.