Safely Handling Solder

Soldering Operations  

Soldering is a process used for joining metal parts to form a bond. It is widely utilized in laboratories and maker spaces with applications ranging from fabrication of electronic components to jewelry making and design. The process inherently poses hazards, so it is essential that best health and safety practices be implemented.  

Hazard Information 
Physical Hazards 

Soldering irons are a source of significant heat when activated. The temperature of the heated tip can reach above 400° C and can cause severe burns to unprotected skin. The tip can also cause considerable damage to loose clothing, hair, nearby electrical wires, and the surrounding workspace. Freshly soldered joints are also extremely hot and must be allowed to cool before handling.  

Electrical Hazards 

Most soldering irons used today range from 20-50 watts, with a standard amperage of around 2.5 amps. It is important to note that wattage does not necessarily dictate the power of the soldering iron, rather, it is a measure of how quickly the iron can heat up. The higher the wattage the faster it will heat up. Be aware of the iron from the moment it is turned on. Touching a hot iron to power cords can melt through insulation fraying or damaging electrical wiring that can cause electrical shock. 

Always plug soldering appliances directly into an outlet and not a power strip. Be sure not to overload the outlet being used as this can trip the circuit and can result in a power outage or even an electrical fire. Never use more than 80% of the max amperage of an outlet. Most Columbia University laboratory electrical outlets are 20 amps, so the maximum usable amperage is 16 amps.  

Respiratory Hazards 

Solder flux containing rosin generates visible fumes. Rosin’s boiling point range starts as low as 100°C and generates solvent vapor when heated to soldering temperatures. Rosin exposure can cause asthma or make existing asthmatic conditions worse. The fumes can also cause eye and upper respiratory tract irritation. Soldering with lead (or other metals used in soldering) may produce fumes that are hazardous. Lead-free solder requires higher soldering iron temperatures and higher acidity fluxes which are more likely to volatize and become inhalation hazards. 

Lead Exposure (from surface contamination) 

The World Health Organization’s International Agency for Research or Cancer classifies lead as a Group 2A Carcinogen, which means it is possibly carcinogenic to humans. The primary route of exposure to lead from soldering is ingestion.  

Hand contact with lead solder or surfaces contaminated with lead solder poses an ingestion hazard as lead contamination can be transferred from hand to mouth. Lead exposure can affect the nervous system, reproductive system, kidneys, and other organs of the body.  

Although lead-free solder is readily available, some solders still contain lead as a major component. As lead is classified as a Hazardous Waste, it must be disposed of as such. Dispose of all lead-containing solder and other products in accordance with the Fundament-L's of Hazardous Waste Management. 

Engineering Controls 

Soldering operations should only be conducted in well-ventilated work areas and work areas having a dedicated exhaust system. Solder in a fume hood or use other local exhaust ventilation. This is especially important for operations lasting more than a few minutes. When using local exhaust ventilation, venting to outside is preferable. If using a system that exhausts into the room, the unit should be equipped with HEPA filtration to remove fumes (condensed particulate) and chemical filters to remove vapors. Ventilation controls must be turned on prior to soldering. Ensure local snorkel/exhaust hoods, benchtop fume extractor, or fan is present and turned on to remove solder fumes from the breathing zone.  

Contact Environmental Health & Safety (EH&S) before setting up a new soldering operation 

In the absence of ventilation/air filtration, soldering operations should be reviewed by EH&S before proceeding. EH&S will review information including type(s) of material used, area size, operating parameters of the area’s ventilations system, and other factors.  

Administrative Controls 

Review the Safety Data Sheet (SDS) for the solder and flux being used for specific safety information.  Waste material will need to be disposed of properly through EH&S using the Hazardous and Chemical Waste Pick-Up Request Form. Please refer to the Fundament-L's, for guidance. Contact EH&S at [email protected] for more information 

Conduct a pre-hot-work check before beginning to ensure all equipment is safe, cords are inspected before use and placed so that they do not create a trip or fall hazard, and hazards are recognized and protected. At a minimum, this pre-hot-work check shall include the following: 

  • Soldering iron and other equipment is in satisfactory condition and in good repair. 
  • Areas adjacent to soldering operations are clear of combustibles and flammables. 
  • Maintain a clean and dust free working area where soldering operations are conducted.  
  • To the extent possible, conduct soldering on a solid, level surface and always return the soldering iron to its stand.  
  • Appropriate fire extinguishers are present and in good condition.  

Turn off all soldering equipment when not in use.  

Whenever possible, substitute lead-containing solder with lead-free solder materials.  

Wet wipe all lead solder contaminated surfaces with a lead removal product. Dispose of clean-up materials and any waste lead wire pieces as hazardous waste. 

Wash hands thoroughly with soap and water after soldering operations and/or before eating, drinking, applying cosmetics, etc. If using lead solder or other products, wash hands with a soap formulated to efficiently remove lead dusts. Do not permit food or drinks in soldering areas 

Wipe down all surfaces and wash hands when done soldering. Never use an air gun or any other form of compressed air or a broom to sweep the contaminated area. This will cause settled dust to become airborne.  

Identify the location of the nearest eyewash and shower and verify that they are accessible and in working condition.  

Handling Soldering Flux 

For disposal, please refer to SDS guidance. Many forms of solder and flux are hazardous and must be disposed of accordingly. DO NOT allow wastewater from cleaning flux to enter drains. 

Training 

Training is the cornerstone of any successful health and safety program and is a fundamental element of EH&S’s commitment to ensuring Columbia University maintains and promotes a safe workplace. All personnel are to complete Shop Safety Training. Training resources can be found on the Columbia Research Website and Trainings are taken through RASCAL. Initial Shop Safety Training TC0600 is required prior to working in any of the Makerspaces and/or Academic Machine Shops. 

Emergency Procedures 

If an accident occurs, report immediately to a supervisor or other appropriate staff member. Seek medical attention, as necessary.  

Contact Public Safety 24/7: 

     (212 )305-7979 for CUIMC 
     (212) 854-5555 for Morningside 
     (212) 853-3333 for Manhattanville 

Contact EH&S during working hours  

     (212) 305-6780 for CUIMC 
     (212) 854-8749 for EH&S for Morningside and Manhattanville  
     Please call Public Safety before 8am and after 5pm.  

SKIN CONTACT  

  • If there is a burn, immediately cool the affected area under cold water for 15 minutes. Do not apply any creams or ointments. Cover with a bandage. 

EYE CONTACT  

  • Using eyewash, flush eyes for 15 minutes while holding eyelid(s) open.  

INHALATION  

  • If irritating fumes are inhaled, immediately move to fresh air.  

INGESTION  

  • Do not induce vomiting  

FIRE  

  • In case of fire follow RACE & PASS Procedures  
  • Rescue: Within the bounds of your personal safety, remove anyone in immediate danger. 
  • Alarm: Pull alarm box located by exits. Call Public Safety and 911. 
  • Confine: Close doors and windows as you leave to confine the fire. 
  • Extinguish/Evacuate: If possible, extinguish fire; if not, evacuate by using stairs or moving into an adjacent building. Never use an elevator. 

Fire Extinguishers  

  • Always know the location of the nearest fire extinguisher. In case of fire, use the fire extinguisher only if you have been trained and it is safe to do so. 
  • Appropriate fire extinguishers must be present in soldering operation areas.  
  • To use fire extinguisher (PASS) 
  • Pull the pin  
  • Aim the hose at the base of the fire  
  • Squeeze the handle  
  • Sweep back and forth 
PPE (Personal Protective Equipment) 
  • Long sleeved shirts and pants that are made of natural fibers (cotton) and closed-toe shoes must be worn. 
  • Safety glasses, goggles or face shields must be used when soldering and clipping wires. 
  • Heat-resistant gloves must be worn when there is the potential for contact with hot surfaces.