Soldering is a process used to join two or more metal components by melting a filler metal, called solder, so that it flows into the joint and solidifies to create a strong electrical and mechanical bond. Soldering is commonly used in electronics to connect wires, components, circuit boards and metal work. Unlike welding, soldering does not melt the base materials. Instead, soldering relies on the lower melting point solder to form the connection, which helps protect delicate components from heat damage. The result is a durable, conductive joint that maintains reliability over time.

Here are the main hazards associated with soldering, written clearly and with an EHS‑focused lens:

• Exposure to fumes: Heating solder and flux can release metal fumes (such as lead, tin, or silver) and flux decomposition products like rosin-based fumes. These can irritate the eyes and respiratory system and may cause long‑term respiratory issues with extended exposure.
• Lead and other metal fume exposure: Lead is a well‑recognized neurotoxin that can cause serious long‑term health effects, including reproductive issues, digestive disturbances, and difficulties with memory and concentration. Direct hand contact or touching surfaces contaminated with lead solder creates an ingestion risk. During soldering, lead oxide fumes may be released, and the process can also generate hazardous fumes from other metals such as cadmium, zinc, arsenic, and chromium.
• Burns from heat: Soldering irons typically operate between 600–800°F (315–425°C). Contact with the iron, molten solder, or recently heated components can cause significant burns.
• Fire hazards: The high temperature of the soldering iron and the presence of combustible or flammable material like paper, cardboard, chemicals, and plastics can create a fire risk.
• Eye hazards: Molten solder can occasionally splatter, and flux can bubble or spit when heated. This poses a risk of eye injury, particularly without safety glasses.
• Electrical hazards: Faulty soldering irons, damaged power cords, or improper grounding can introduce shock risks.

• Do not eat or drink in areas where soldering is performed.
• Wash your hands thoroughly with soap and water after completing soldering tasks.
• Follow manufacturer’s instructions for the safe operation of the soldering unit.
• Review the Safety Data Sheets (SDSs) for all materials being used. Retain SDS sheets for all soldering materials onsite.
• Check soldering equipment for any signs of damage before and after each use. Report any defects to your supervisor immediately.
• Soldering iron precautions: 
  • Avoid touching the heating element or tip of the soldering iron.
  • Always place the soldering iron in its designated stand when not in use; never set it directly on the work surface.
    Keep the cleaning sponge damp during operation.
  • Turn off or unplug the soldering iron or whenever it is not actively being used.
• Do not use solder containing lead or lead oxide. If this is not feasible for your application, contact EHS@rpi.edu for assistance.
• Develop a Job Hazard Analysis (JHA) for your soldering work and submit it to EHS@rpi.edu. 

• Soldering is prohibited in any area where explosive materials or flammable/combustible/toxic gases are present.
• Keep your work area clean and uncluttered: Remove paper, cardboard, chemicals, and other combustible materials from the soldering station. Keep a 10 foot radius around the soldering station clear of these materials at all times.
• Use a stable, heat‑resistant work surface. Soldering irons get extremely hot, ensure soldering surfaces are non‑flammable.
• Always place the soldering iron in its stand. Never set a hot iron on the bench or on any surface that could burn or ignite.
• Inspect equipment before use: Look for frayed cords, damaged plugs, or loose connections that could create sparks or excessive heat.
• Never leave a powered soldering iron unattended. Turn it off or unplug it every time you leave the soldering area.
• Allow components to cool completely before touching or placing them near combustible or flammable materials. Newly soldered parts can stay hot long after the iron is removed.
• Remove chemicals,  flammable liquids away from the area. This includes alcohol-based cleaners, aerosols, and solvent wipes.
• Ensure a fire extinguisher readily accessible. A Class ABC extinguisher is typically appropriate for electronics workspaces. If a fire extinguisher is not available, contact the Facilities Customer Service Center (FIXX) and submit a work order request.
• Know emergency shutdown procedures. Be familiar with how to safely disconnect power and how to respond to an equipment failure.

Soldering fumes and particulate byproducts are hazardous and precautions need to be taken to prevent inhalation. Fumes and particulates must be extracted and filtered by mechanical means, such as:

• Fume hoods: Fume hoods are the best option for soldering as fumes are immediately extracted and brought outside of the building. Fume hood surfaces, including the work surface, are non-flammable. If a fume hood is to be used for soldering, ensure that it is vacated of chemicals and that the work surface does not contain chemical residue.
• Soldering fume extractor units equipped with both HEPA (high efficiency particulate air) and carbon filters.
  • Build a maintenance schedule to replace filters prior to their end of life by following manufacturers recommendations.
• Snorkel style fume extraction, vented either through tapping into a fume hood exhaust duct or air duct or one that recirculates air within the space and is filtered by both HEPA and charcoal filtration.
  • If the fume hood duct is to be tapped into for mechanical exhaust ventilation, please contact EHS@rpi.edu. EHS will assist in identifying your next steps.

When soldering is completed. Ensure that the soldering workspace is cleaned. If soldering materials are cleaned off of the work surface, collect all items used (towels, sponges, etc.) in a container as it is now considered regulated waste.

For more information, visit the EHS Regulated Waste Management webpage for more information, including regulated waste labels and pickup requests.