Lead Solder Hazards

Solder that contains lead is toxic.  However, when the solder is handled and treated appropriately, there is minimal hazard for any person working with the solder.  The digestive system is the primary means by which lead can be absorbed into the human body.  The basic rule of thumb for lead is:  "Do not eat lead, in any of its forms."

Skin contact with lead is, in and of itself, harmless – but getting lead dust on your hands can result in it being ingested if you don’t wash your hands before eating, smoking, etc.  In addition, it’s possible that the lead dust could be transferred to someone else - a child, for instance - through direct contact and then that person could ingest the lead.  An often overlooked danger point is the habit of chewing fingernails.  The spaces under the fingernails are great collectors of dirt and dust.  Almost everything that is handled or touched may be found under the finger nails.  Ingesting even a small amount of lead is dangerous because it is a cumulative poison which is not excreted by normal bodily functions.

Soldering circuit boards with lead core solder is very common in the Accelerator Division.  To evaluate employee exposure to lead, a sample of desks where soldering is performed was tested.  One desk exceeded the Fermilab standard for lead surface contamination (0.5 microgram per square centimeter).  The desk was cleaned and tested again.  The second result did not exceed the standard.  

On desks and work benches where soldering is performed, you should follow several hygiene practices:

• Do not eat or drink in the work area.
• Do not store food or drink in the work area.
• Wash your hands thoroughly after soldering.  Handling a cigarette or food with solder-contaminated fingers carries the possibility of ingesting lead-containing solder.
• Drinks should not under any circumstances be consumed in the soldering work area. 

It cannot be stressed enough to thoroughly wash your hands after soldering.  Do not forget to clean your work area daily.  Wiping your desk down with a wet rag or cleaning the desk surface with Windex and a Kimwipe will go a long way in minimizing ingestible lead contamination from your work surfaces.