Safe Soldering Techniques

Health Hazards

Lead (Pb) is a known neurotoxin and can pose other significant chronic health effects, such as reproductive problems, digestive problems, memory and concentration problems, muscle and joint pain. Therefore, solder that contains lead is considered to be toxic. If lead-containing soldering material is not safely handled, workers may be inadvertently exposed. However, when the solder is handled and treated appropriately, there is minimal hazard to any person working with the solder. Potential exposure routes from soldering include ingestion of lead due to surface contamination and inhalation of soldering fumes. For assistance or if you have exposure concerns, contact your EHS Coordinator, Todd Numan (tnuman@mit.edu). EHS can also do wipe tests for lead to determine if there is a concern.

General Safety Precautions

  • To avoid skin burns never touch the tip/element of a soldering iron, which can be 400°C, and hold the wires to be heated with tweezers, pliers or clamps.  Wear appropriate personal protective equipment (PPE), follow manufacturer’s instructions, and read the solder safety data sheet (SDS).
  • Avoid inhalation of lead soldering fumes. Work in a well ventilated area or use local exhaust ventilation.
  • Avoid ingestion of lead by surface contamination.  Keep soldering areas clean and properly manage lead soldering waste (see below).  Personnel should not eat or drink in soldering areas and should always wash hands with soap and water after completing soldering work.
  • Turn unit off or unplug the iron when not in use. Soldering stations that feature an automatic shut off not only extend the life of tip, iron and station, but provide an additional measure of fire safety.

Personal Protective Equipment (PPE)

  • Protective Clothing – long sleeve shirts and pants that are made of natural fibers (cotton) and closed‐toe shoes should be worn during soldering activities. Heat resistant gloves may also be prudent.
  • Eye Protection – Solder can spit – Wear safety glasses, goggles, or face shields.

Waste Management

Lead soldering waste is considered a hazardous waste. If you generate lead soldering waste, EPA and MA/DEP regulations require that you properly collect and manage the waste in a satellite accumulation area (SAA). This could even be a sealed plastic bag with a red tag.  The generator must inspect the SAA containers weekly and ensure compliance with the following:

  1. Storage – Only one lead waste container is allowed at each SAA.
  2. Labeling ‐ every container in a SAA must be properly labeled. The approved labels (Red Cards) will be supplied by the EH&S Office and you will need to include the following information: the words ‘Hazardous Waste’, full chemical name of the waste (Lead), hazard classification (Toxic), PI/Generator/location information and remember to date the container only when it is full.
  3. Closure ‐ All containers must be closed at all times except when adding waste.
  4. Removal ‐ Full containers must be dated and promptly removed from the SAA within 72 business hours. Please contact the Environmental Health and Safety Office for removal of waste using our on‐line pickup request:  https://mit.quickbase.com/db/bms438qt8?a=nwr