Soldering Air Quality Hazards and Solutions
William G. Nicholson
U.S. Air Force

Abstract Air quality has become questionable with recent increased production and soldering procedures conducted by the Avionics Intermediate Systems Shop at Charleston Air Force Base. With an unknown quality level of air within the soldering area there is a need for a sample to be taken and options to be considered to improve the working environment. Even though the air sample may reveal that levels are under threshold levels, the simple fact that employees are uncomfortable doing the task may warrant solutions as if the sample was above limits. Those changes would not be required by anyone outside of the Air Force, but would be considered based on employee well-being. This research paper will reveal the findings of the air quality sample, the methods of testing, and countermeasures intent on improving air quality. Most research has concluded that the soldering flux is the real contaminate and that the lead based solder does not become airborne during the process; which is exciting in the fact that expanded measures are not needed to account for lead. There are many solutions available to correct the air quality and this paper will assess the most applicable and cost effective. Keywords: soldering, flux, rosin-core, air quality, ventilation

Soldering Air Quality Hazards and Solutions
The current set-up for soldering avionics component parts has questionable ventilation to account for the increased tasks that involve this practice. New procedures were developed to re-solder batches of circuit cards at a time which means the process occurs for hours as opposed to the past when it may have been minutes a day. Typical early symptoms are watery and prickly eyes, runny or blocked nose, sore throat, and coughing, wheezing or breathing difficulties. These may start within minutes of exposure or be delayed for several hours, so that their link to work may not be immediately recognized. However, improvement at weekends and holidays often points to the symptoms being job related. First, the MSDS’s (Material Safety Data Sheets) for Rosin-Core Solder and Flux will be examined for a chemical makeup. Solder is used to join electrical components to one another and Flux is used to prevent oxidation and ensure a strong bond between components. It should be noted that current Air Force instructions on the process require the technician to use Flux, and it is not optional. After the chemical make-up is addressed, the air quality survey report will be accessed to determine the levels of those toxins in the air and also to reveal the process of taking the sample. OSHA PEL’s (permissible exposure limits) for those toxins will be cross referenced with the air quality sample to see if those PEL’s are reached within the avionics maintenance shop. Once those determinations are made, solutions can be considered to filter the air, move the operation to a larger area, or nothing if it is not warranted. Ventilation methods from several sources will be compared to find the most feasible application if it is warranted by the air quality sample.
Upon review the current MSDS’s for Solder and Flux, the chemical compounds become apparent along with their controls. There are warnings about contact, ingestion, and splash protection but since those hazards are covered by wearing protective gloves and goggles, the focus will be only on the fumes and inhalation issues presented by the process. The MSDS for soldering flux states that it contains two dangerous components (Kester, 2003). Propan-2-ol at a concentration of 50-100% and Rosin at 25-50% are the only two components of Flux. The MSDS also states that those two components may have the following effects: * Have a narcotizing effect * Irritating to the eyes * May cause sensitization by skin contact * Vapors may cause drowsiness and dizziness
The MSDS for Rosin-Core Solder states that it contains lead, tin, antimony, copper and rosin (Bow Electronic Solders, 1999). Since the lead and tin make up over 90% of the material, those will be the focus of this research as the other components are negligible. These hazardous compounds are known to cause the following after chronic overexposure: * Damage to blood, nervous, and kidney systems * Anemia * Reproductive health and infertility
The MSDS’s are believed to be completely accurate as they were pulled recently from the Air Force MSDS database that is updated annually and they still contain dates from 1999 and 2003 respectively. This indicates that there are no changes to the chemical make-up of either product from the date of the MSDS preparation to the present. The OSHA website was consulted particularly part 1910 Subpart Z to verify that the PEL’s required by law were the same as the PEL limits on the MSDS’s (OSHA, 2014). The MSDS matched OSHA’s limits and also stated that lead is another subpart in OSHA due to the extreme danger it poses. Lead has a PEL of 0.05, Tin 2.0, Propan-2-ol 980, and Rosin 0 .1 with all units of measurement being in milligrams per meter cubed (mg/m 3).
The process for the air quality sample from Bioengineering was performed using the OSHA standard for air sampling by using a personal sampling pump to draw a known volume of air through a mixed cellulose ester membrane filter contained in a polystyrene cassette. This process is the standard for air sampling in the Air Force. The samples are then transferred to a lab at Hill Air Force Base for processing and results. The results of the air quality sample indicated that none of the elements present were anywhere close to the PEL set by OSHA. The amount of lead was negligible as was tin and rosin. The concentration of Lead was less than .001mg/m3. The concentration of Tin was less than .001 mg/m3, Propan-2-ol was 50 mg/m3 and Rosin at less than .01 mg/m3 (Bioengineering 2012). Based on previous studies most tests concluded that the rosin was the most irritable to the technician being that it is the quickest to turn into fumes and at a higher concentration. The air quality sample holds up the fact that the air is within OSHA limits. There are a few concerns with the sample as it is hard to use a suction device that can mimic an actual inhale of fumes. The device used had a constant rate of influx into the chamber but a human can breathe at different intensities and often does. The sample was also taken on a cool, low humidity day when the air circulates well. Higher temperatures and less than effective cooling in the area could make the soldering room hold more contaminates in the air especially coupled with high humidity or stagnant air. Those concerns are not substantiated, just theory and the air quality sample is presumed to be correct. The Bioengineering Department did heed to the request to take the air sample between the work station and the technician’s face which is where the fumes are most concentrated. This was beneficial because a sample of just air in the room may not show levels anywhere close to what is immediately inhaled. Palmer and Crane conducted a study that found that with a sample of 152 female workers symptoms of recurrent, persistent wheeze and/or chest tightness were reported by 75 (49%) of interviewees; 36 (24%) gave a history typical of occupational asthma and six more (4%) a history of pre-existing asthma worsened at work. Twenty-one (14%) of the workforce complained of recurrent breathlessness on moderate exertion; 41 workers (27%) had work-related symptoms of the nose or throat and 25 (16%) had work-related eye symptoms (Palmer, K. & Crane, G., 1997). This study may indicate that the PEL’s for OSHA may be outdated and it may require another look by OSHA to update the hazards of soldering fumes. Until that can take place, for the purpose of this research the test sample taken will be presumed safe.
One consideration to be made is that even though the levels are below OSHA standards, there is still room for improvement for comfort of the employee. The OSHA standards for noise may not be exceeded in certain workplaces but still may be uncomfortable to many people and the same holds true for air quality. The complaints may justify finding solutions even though the air quality sample was not a justification. There are several ways to improve on the process by using management controls and engineering controls. Looking from a cost-benefit side, the most practical is to retrain many of the technicians on technique and simply tilting the head to the side or using the magnifier between the technician and the work as it prevents a straight shot for fumes to enter the persons eyes, nose and mouth. These are simple techniques and just a start to preventing some irritation. Secondly, Asfahl and Rieske have touched on many design principles for improving air flow in toxic areas. The most practical would be a type of filter or scrubber that would allow for contaminates to be filtered without losing cooled air to the outdoors (Asfahl, R. & Rieske, D., 2010). Engineering controls could be used to basically relocate the soldering area to a larger by within the shop. With the increased production and soldering, it would not be difficult to move the operation to an adjacent room with much more air flow. Many of these ideas would improve but one by one some can be eliminated. The ventilation system as a whole would be the best for quality of air throughout the workplace but not cost effective or quick to implement. Relocating the process benches would be cost effective and timely but still may not reduce complaints due to the fact that the technician is still required to have their face over the work. The air around them may be more pure but right over the work the fumes are still present. The best method and most cost effective would be to use small portable air systems. They provide a solution to ventilation problems without major ventilation overhauls or workplace changes. Ventilation, either local or dilution (general), is probably the most important engineering control available to maintain a healthy work environment. Several manufacturers offer different styles of source-capture fume extractors for solder fume control, solder pot and wave soldering fumes. Configurations include bench top, wall-mounted, portable, and floor models. These compact and energy-efficient systems feature quiet operation, convenient mobility, and high efficiency filtration media including HEPA and/or Activated Carbon (Sentry Air Systems (2013). ESD safe units are available for those concerned with electrostatic discharge while working with sensitive electronic equipment.
Modular designs make solder fume extractors a convenient and effective solution for solder fume control needs. Based on the research, the air quality is well within limits but a cheap alternative could improve the workplace without having a standard to make the improvement mandatory. These extractors will basically suck the fumes from the work surface between the circuit board and the technician’s face and filter the air with clean air returned to the room. The only consideration is that additional filters must be purchased to change at regular intervals but still the most cost effective solution. The research did pose another question based on some other research in the area. The cases reported of asthma from soldering technicians working in areas that adhere to the OSHA standard may require new testing and PELs to be recommended. The same is true in the avionics workplace where the air quality sample was well within limits but employees had many complaints. Past procedures using toxic substances such as asbestos and coal did not show any signs of health implications for decades and rosin fumes may require more research based on the number of complaints. Given the research, an accountant may deem the proposed solutions unnecessary but a manager should consider the low cost improvement as a psychological approach of hazard avoidance.

Resources
Bioenvironmental (2012). Industrial Workplace Survey (Avionics). JB Charleston Bioenvironmental Department
Bow Electronic Solders (1999). Rosin Core Solder Material Safety Data Sheet. Sayreville, NJ
Kester (2003). Soldering Flux Material Safety Data Sheet. Des Plaines, IL
Palmer, K. & Crane, G (1997). Respiratory Disease in Workers exposed to Colophony Solder Flux Fumes: Continuing Health Concerns. Retrieved from http://www.ncbi.nlm.nih. gov/pubmed/9604483
Sentry Air Systems (2013). The Hazards of Solder Fumes. Retrieved from http://www.sentryair.
.com/solder-fumes.htm
Asfahl, R. & Rieske, D (2010). Industrial Safety and Health Management (6th ed.). Upper Saddle River, NJ: Pearson Education Inc.