Dwayne Reid wrote:
> My partner's friend forwarded a newsletter article titled "Rollback
> the Lead-Free Initiative".
>
> The thoughts expressed in that article pretty much match my views but
> I thought that I'd pass a link to the article and see what thoughts
> others on this list might have.
>
> <http://www.sigcon.com/Pubs/news/10_01.htm>
>
> FWIW - my own experience with Tin Whisker Formation was at a local
> power generating plant.  The problem was severe enough that I
> recommended complete replacement of the affected systems.  They did
> just that.
>
> Many of those tin whiskers exceeded 6mm length.

In the article, the author states:

"My conclusion? SAC solder is markedly worse for the environment than 
lead-based solder. We are not saving the environment by moving to SAC 
solder, we are damaging it. Here is a link to the full report:
http://www.epa.gov/opptintr/dfe/pubs/solder/lca/index.htm"

I'd be interested to find out how he arrives at that conclusion. The 
following is an excerpt from the report:

"The toxic characteristic leachate procedure (TCLP) leachability
study is based on a standard EPA TCLP test protocol using acetic acid, a 
substance known to
readily leach lead. It is unknown to what extent these test conditions 
represents actual landfill
ES-29
conditions, which can vary dramatically over the lifetime of a landfill. As 
a result, the alternate
analysis was conducted using the detection limit of lead during the testing 
as a lower bound to
determine the sensitivity of the results to the lead leachability.
Results of the analysis indicated that even with the assumption that the 
lead essentially
does not leach (i.e., assuming the study detection limit for the 
leachability of lead), the SnPb
alloy impact scores are still at least 2.5 times higher than the score of 
the next closest alloy for
public non-cancer impacts, and a full order of magnitude higher for aquatic 
ecotoxicity. The
relative differences between SnPb and the lead-free alloys are far less than 
in the baseline
analysis. This analysis suggests that any elevation of the leachability data 
for SnPb due to the
aggressive nature of acetic acid towards the lead-based solder was unlikely 
to have changed the
overall impacts for SnPb relative to the other solders. The SnPb alloy would 
still have the higher
potential impacts for both public non-cancer and aquatic ecotoxicity than 
the other solder alloys,
based primarily on its relative toxicity."

Now, I understand what Dr. Johnson is saying. He admits that the lead is 
more toxic, but other alloys are worse based on other criteria -- all I'm 
saying is, there's nothing that I can readily see in the report, that 
supports his conclusion.

Vitaliy 

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