(This column, which originally appeared in Global SMT & Packaging magazine 6.6 (June/July 2006), is also available as a free PDF.)

While the US prepares for festivities marking another 4^th of July celebration, the EU will be embarking on its new Restriction of Hazardous Substances (RoHS) adventure. This well intended but now clearly misguided piece of legislation that was designed to make the environment better has slowly but surely been shown to be anything but ‘green’, mostly because of its stance relative to lead in electronic solders. Lead-free electronics has become the major sticking point in this otherwise somewhat reasonable piece of legislation that also restricts the use of a number of naturally occurring elements including cadmium, hexavalent chrome and mercury along with some organic compounds (PBB and PBDE) commonly used as flame retardants in plastics and laminates, which have been shown to have possible links to cancer. Unfortunately, most of the campaign has been carried out under the flag of lead-free, perhaps because lead has been so widely vilified in the press as a poison that preferentially targets children, or perhaps because the removal of lead from electronic solders was the most visible and would have the greatest impact both industrially and economically; yet in truth, lead in electronic solders accounts for less than ˝ of 1% of all lead used globally on an annualized basis.

As this represents the last time that this column can make the case before the law kicks in, it will recount again the reasons why lead in electronic solders should be exempted from the RoHS provisions. First and foremost are the environmental arguments against the ban of lead in electronic solders. To that end, one should know that lead in electronic solder has never been documented to have caused a single individual any harm from normal use. Moreover, lead from electronic solders that does wind up in landfills does not leach into ground water. Even with years of legacy lead from many other sources, such as batteries and painted structures, all but a few (~3) landfills with waste comprised of significant quantities of lead deposited from nearby head lead use industries. Several studies from both universities and the US EPA have indicated that on the whole, lead-free electronics appear to be much less environmentally friendly. The primary negative of lead is its toxicity, which for lead, as metal or in an alloy, is highly unlikely to cause harm.  

Considering now the alternatives being adopted, most lead-free solders contain substantial percentages of silver (~ 3 to 4%) and silver is toxic to microbial life and fish larva. Silver is thus a toxic real risk. Add to that the fact that lead-free solders typically require significantly higher temperatures to solder meaning that more energy is required and will be consumed on a continuing basis adding unnecessarily to global warming. Then there is the fact that tin use, will increase, while tin resources are significantly lower than those of lead. This means that new tin mining will likely be required. Unfortunately, some of the richest tin mines are in rain forests, which will likely be clear cut to get to the tin deposits.  

Turning attention to the economics of lead-free (other than wasted energy cited above). The conversion cost, it has been calculated, will likely run into the several tens of billions of dollars and could top 100 billion while the environment is made worse. (How many ways might that money be better spent?) The reliability of lead-free solders is still a big uncertainty and concern among reliability experts. There are still numerous effects (voiding, tin whiskers, etc.) whose causes are neither well understood nor predictable. As evidence, some products converted to lead-free are reportedly already running return rates 3% to 4% higher than products that were soldered using traditional solders. Return costs are 10 to 50 even 100 times greater than catching the defect before it reaches the market. Moreover as one reliability sage observed, “Reliability is best measured not by the return of the product but by the return of the customer.” Additionally, traditional tin-lead solders will continue to be used by military and aerospace manufacturers who must have the highest levels of reliability, resulting in a dual path which will create ongoing logistical headaches. Then there is the matter of product innovation will continue to be delayed as engineers are diverted from solving real technological problems associated with product development to solving a ‘problem’ that never actually existed in the opinion of most scientists.  

Clearly there are compelling and persuasive arguments to be made in favor of traditional tin-lead solders and nothing that can be argued against it beyond blind emotionalism. But perhaps the most compelling argument is being made by the EU’s other mandate, Waste Electrical and Electronic Equipment (WEEE), the provisions of which mandate the recycling of electronic products, making all of the concerns of lead in electronic solders completely moot.  

Wanting to end on a positive note, there is a strong grassroots movement afoot to ‘push back’ on the lead-free portion of legislation in favor of the environment. The Push back website (www.rohsusa.com) has links to a myriad of references which substantiate the arguments made here. Moreover, there are signs of willingness on the part of some EU legislators to listen to scientific evidence that lead-free solders represent a greater risk. This is heartening news. When all is said and done, there will always remain the simple unvarnished truth about this matter. Fortunately, the truth is as perennial as the grass and has a way of continually popping back up no matter fiercely one might try to keep it down.

Keywords : Joe Fjelstad, RoHS, lead free

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