Dear Lee (and all),

I would like to comment on the TCLP data presented by my colleague, Karl
Seelig.

AIM did have CASTIN (Sn/Ag/Cu/Sb) bar, paste, and a crushed PCB that was
assembled with the solder tested to TCLP test method 1311/6010.  In
addition, Sn/Cu and Sn/Ag alloys also were tested to these standards.  You
are correct in that none of these tests demonstrated a failure.  This
testing was performed by Environmental Science Services (ESS) Labs in
Cranston, RI.  These test results are available for review at your request.

The above TCLP testing was performed to Federal standards.  RCRA has
determined that the following metals must be tested for by TCLP: Arsenic,
Barium, Cadmium, Chromium, Lead, Mercury, Selenium, and Silver.  Antimony
has not been determined as an element that must be tested for by TCLP.  A
complete listing of the elements that fall under TCLP may be found at
www.frwebgate.access.gpo.gov/cgi-bin/get-cfr.cgi .

It is interesting to note that the report refers to drinking water
standards.  Drinking water has justifiably been assigned the most stringent
standards of all classes of water.  The standards are so strict, in fact,
that if one was to run drinking water directly out of the tap through a
drain and collect it for testing, it is likely that the water would fail to
meet applicable standards. Drinking water and effluent wastewater have
nothing to do with each other, as far as acceptable metallic levels are
concerned.  Wastewater from soldering operations is passed through waste
streams to solid landfills, not through drinking water systems, and thus in
judged by a different standard.

I hope that this is helpful and I look forward to the lively debate that may
ensue!

David Suraski
AIM
-----Original Message-----
From: Lee Wilmot <[log in to unmask]>
To: [log in to unmask] <[log in to unmask]>
Date: Monday, November 01, 1999 6:20 PM
Subject: [LF] Impressions from Int'l Summit on LF Electronics Assemblies


>     Hello Everyone,
>
>        While several subscribers have commented on the Minneapolis summit,
>     I have not seen in these comments, nor in the vast majority of papers
>     presented, much in the way of comparitive analysis of environmental
>     impact of the LF alternatives. There seems to be two specific areas
>     which are not being addressed - relative environmental toxicity of the
>     LF alternative, and relative recycleability of the end-of-life (EOL)
>     LF product. Perhaps the FEAR factor of a lead ban is driving such
>     abbreviated evaluations, but market share is a powerful driver too.
>
>     1. Comparitive leaching
>        These shortcomings are surprising since the alleged reason for
>     developing LF electronics assemblies is mainly environmental, even
>     though no data exists which links any adverse enviromental impact from
>     lead to electronic solder or assemblies. The only adverse lead impact
>     on the environment that we heard was that from Katsuaki Suganuma of
>     Osaka University. He showed that 1996 and 1997 monitoring data from
>     over 2000 waste storage areas in Japan showed 0.3%, or roughly 6 sites
>     had lead levels in the groundwater (GW) of 1 ppb or more. There was no
>     linkage to waste electronic products presented. This data is
>     consistent with the 1991 data presented by Jeff Miller of the Lead
>     Industries Association (LIA) wherein two of 146 US municipal landfills
>     analyzed had GW contamination, and both were traced to industrial
>     waste disposal, a practice banned long ago in the US.
>
>        The immobility of lead in the GW should not be surprising given the
>     insoluble precipitates that lead forms with sulfates. One reported
>     study of ancient Roman lead smelters revealed an estimated one yard
>     movement in two thousand years! By comparison, we heard of the high
>     levels of leaching of both silver and antimony from Ed Smith of K-Tec.
>     Specifically, of the eight solder alloys tested, antimony and silver
>     leached from all forms with all leach tests. The only presenters that
>     I recall addressing the toxicity of leachate from LF alternatives were
>     Karl Seelig of AIM Solder and Ken Snowden of Nortel. Of interest is
>     AIM's TCLP results (which were not in the paper or on their website)
>     which did not show leaching above TCLP hazardous waste levels for
>     either silver or antimony.
>
>     2. Recycling solution
>        The response to the toxicity concerns of LF alternative solders was
>     that even LF electronic assemblies need to be recycled. While this is
>     true, it is more critical that they be recycled because of the higher
>     relative mobility of the leachate from say silver. The implementation
>     issues for recycling electronic products is underestimated in my
>     opinion, and in Alan Rae of Cookson's presentation. I don't think that
>     too many in the industry understand the enormity of the reclaim cycle
>     that he described (from consumer to collector to dismantler to refiner
>     to processer to fabricator and back to the consumer). In fact, isn't
>     this the key issue in the proposed rev 3 of the WEEE directive? (i.e.
>     who's going to pay to collect WEEE?)
>        For nearly 20 years, it has been illegal to dispose of industrial
>     waste that tests "positive" for TCLP characteristics such as lead, or
>     silver, and the other six RCRA metals. Hence, both PWB and PWA mfgrs
>     in the US have had to recycle these byproducts, as they are prohibited
>     from being landfilled (or incinerated) at non-TSD (treatment, storage
>     or disposal) facilities. These restrictions have not applied to
>     consumer wastes, but there's been successful consumer recycling
>     programs for used oil, newspapers, certain plastics, aluminum cans,
>     etc. No reason why one for consumer electronics couldn't be started.
>
>     3. Recycleability
>        A key area in selecting a LF alternative is whether the EOL
>     products can be recycled at the same or higher rate than the present
>     SnPb products area. What was quite surprising to hear from Ken
>     Snowden's presentation is that major copper smelters in both North
>     American and Europe will not take material with more than 20 ppm
>     bismuth in it! This could be a real show stopper for solders
>     containing Bi, unless shipping these EOL products to Japan is done, as
>     Japanese smelters reportedly do not have such restrictions.
>
>        Unpopulated PWBs are roughly 20% Cu and 1% Pb. We heard that PWAs
>     are about 3% Pb. Assuming that the components and added solder double
>     the weight of the PWB, the PWA would be about 10% Cu. The 3% Bi solder
>     that Panasonic developed would therfore, result in about 2500 ppm Bi
>     on the PWA. After EOL, where would these WEEEs w/Bi be recycled if the
>     major Cu smelters in N.America and Europe won't take them?
>
>     4. Other environmental issues
>        We heard one paper on the technical abilities of an immersion
>     silver finish on PWBs. However, PWB fabricators must meet an extremely
>     low discharge limit for silver. Typically 0.05 to 0.15 ppm, much, much
>     lower than lead and other PWB metals. Given the high aquatic toxicity
>     of silver, PWB shops will have to use extreme care to prevent wiping
>     out the biological activity of the sewer authority to which they
>     discharge.
>
>        The International Chamber of Commerce's (ICC) Business Charter for
>     Sustainable Development contains 16 principles. Based on what I heard
>     and read the the Minneapolis summit, I'm not sure that the following
>     have been addressed thoroughly with the LF presentations that I heard:
>
>     "6. Products and services
>        To develop and provide products or services that have no undue
>     environmental impact and are safe in their intended use, that are
>     efficient in their consumption of energy and natural resources, and
>     that can be recycled, reused, or disposed of safely."
>
>     "9. Research
>        To condust or support research on the environmental impacts of raw
>     materials, products, processes, emissions and wastes associated with
>     the enterprise and on the means of minimizing such adverse impacts."
>
>     "13. Transfer of technology
>        To contribute to the transfer of environmentally sound technology
>     and management methods throughout the industrial and public sectors."
>
>        To sum up my concern, the Assembly breakout group's #1 concern/
>     roadblock was as follows:
>
>        "Insure that the alloy of choice won't be banned in ten years"
>
>     Succintly stated. In my opinion, the LF development efforts have been
>     focused on the technical issues of melting point, solderability,
>     wetability, reliability, etc, which they need to, but they also need
>     to focus on the ICC principles stated above. From what I heard, many
>     of the technical issues have been addressed, but few of the
>     environmental impacts have been.
>
>        Nortel's SnCu solder holds promise if high temperature substrates,
>     HASL oils and components can be developed, as does Toshiba's SnZn
>     solder if application issues can be developed. I'm not comfortable
>     that solders containing silver, antimony and bismuth wont' be banned
>     in ten years if lead is banned now.                        Lee Wilmot
>                                                                HADCO Corp
>
>     NOTE: These views are mine, and not necessarily those of my employer.
>
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IPCWorks -October 25-28 featuring an International Summit on Lead-Free Electronic
Assemblies.
Please visit IPC's Center for Lead-Free Electronics Assembly
(http://www.leadfree.org ) for additional information.
For technical support contact Gayatri Sardeshpande [log in to unmask] or 847-790-5365.
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