Soldering safety, solder smoke, leaded/unleaded solder?


Its been an unending debate on how harmful the solder smoke is. As a young man, i am concerned on whether my daily soldering will affect me later. Whether short term or long term. (Especially since the smoke always seems to be attracted to the face… for some strange reason). I believe many share the same concern.
Except the usual safety precautions when handling solder iron e.g. to prevent burns, what other precautions especially related to solder smoke should be taken?
Any reason (health-wise or for better results) for me to use either leaded or unleaded solder wire over the other?
Is using a solder fan effective? or does it just spread the smoke and make you … ‘a passive smoker’.

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So ive come to one conclusion: the surest way and the best place to start would be to test samples of solder smoke and come up with a report.
This is going to be fun!

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Thesis statement:
Long term exposure to solder smoke causes lungs complications among other illnesses.

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Yes @emmanuel, solder fumes should not be inhaled under any circumstances.



I’ve done some literature review and what I’ve found surprised me. I thought i should share it here:



Soldering is the process of combining two metals via a third metal (the “joint”) with a lower melting point than the base metals. In this procedure, the two base metals (mostly copper, silver or iron in electronic circuits) are not distorted and only the filler metal (solder wire) is melted.



In a research done by Weller®, a soldering products manufacturer, explains that “at least 20% of the employees working in the soldering area show clinical symptoms of asthma caused by the work environment” in studies that have been done on workers mostly in the United States and England in the electronics industry.
Solder can be categorized into two main categories based on its constituting elements: lead and lead-free solder.



Leaded solder has been being used for decades now. It offers smooth, silver bright (in color) finishing. Its preferred due to the ease it offers when soldering: a lower melting point and a good looking finishing. However, Its numerous health effects fuels user’s demand to rule it out.
Lead is used in the soldering process in the form of lead/silver filler metals. When heated, lead oxide fumes are formed. Excessive exposure to lead oxide fumes can result in lead poisoning. Lead is absorbed through the mucous membranes of the lung, stomach (Don’t eat while soldering), or intestines and then enters the bloodstream. Worse, lead absorption is cumulative as it is slow to leave the body.
Symptoms include loss of appetite, indigestion, nausea, vomiting, constipation, headache, abdominal cramps, nervousness, and insomnia. Lead is absorbed through the mucous membranes of the lung, stomach, or intestines and then enters the bloodstream".
On the extreme, absorption of lead is known to cause birth defects, cancer and other reproductive harm and may result for example in damage to the blood and neurological systems.
Ventilation is probably the most important engineering control available to the safety and health professional to maintain airborne concentrations of lead at acceptable levels. It is advised to solder only with adequate ventilation and respiratory protection when necessary. You should get suitable ventilation equipment and ensure that the fumes are sucked outside. In other words, the traditional soldering with a fan blowing the fumes away from your face but circulating it within the room is primitive and useless. You’ll need a dedicated ventilation system.
Wash thoroughly before eating, drinking or smoking. There is danger from using lead solder and getting it on your hands and then eating. So don’t eat while soldering.



Lead free solder is believed to offer health wise safer soldering over ease of soldering. Its higher melting point (217 oc compared to 182oc of leaded solder) demands hotter solder tip.
Surprisingly, Research has shown that the fumes and vapor emanating from lead-free solders may
be more dangerous to workers and to the environment than those emitted by traditional
lead containing solders. According to a study by the Danish Toxicology Centre, silver, a standard constituent of lead-free alloys, was found to be several orders of magnitude more eco-toxic than lead. In addition, some of the other metals used in lead-free alloys were shown to have uncertain toxicological results.
It’s a case of the best intentions seem to have unintended consequences.




  1. The Hazards of Solder Fumes,
    © Sentry Air Systems, Inc. 2016
  2. What are the disadvantages of lead-free solder vs. lead solder? 15th July 2015
  3. Leaded solder
  4. Lead-Free_Solder_Fumes_Increase_Need_for_Fume_Extraction.pdf
    Lead-Free Solders Increase the Need for Bench-Top Fume Extraction


In a research i did between 6th to 7th of december, I sampled labels of solder wire rolls from fifteen electronics shops. Twelve of the labels read 63% tin, 37% lea, 2% flux.

Does anyone know if the country has any regulation on leaded or lead free solder?

I advice use of dedicated vents, not fans, in your personal, industrial or lab works.