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When Electronics Get Five O'Clock Shadow

whiskers.gifWhere were you on May 19, 1998 when the Galaxy 4 communications satellite failed? If you were answering your pager, grabbing some cash at an ATM, or completing a credit card transaction, you were probably in a state of frustration. That's because, miles above the Earth, microscopic tin whiskers formed a conduit between two metal contacts, short-circuiting the satellite's central processor.

Who knew that metal could grow nano-whiskers? I certainly didn't. I have to admit, the thought conjures up images of 1950s "B" science fiction. Actually, engineers have known about the problem since the 1940s, and they solved it by adding a 2 -3% lead solution to the tin plating used in electronic assemblies.

Lead? Guess they didn't know back then that lead's not conducive to healthy neural pathways, especially juvenile ones.

But it's hard to change habits and improve on the technical experience formed over the last 50 years, especially considering that lead worked really well. And the risks involved in implementing new solutions to get the lead out seem to outweigh the benefits of elimininating from the environment the small amounts of the element in question. But electronic gizmos are proliferating at an astonishing rate, and they eventually end up in landfills.

When you talk to technology corporations about developing lead-free electronics, they cite the huge investments involved in satellite circuitry, or even high-end home electronics like HDTV, and admit that they're leery. They fear that near-term solutions to the metal whisker problem might not hold up for the long run, and could unleash a chain of failures of Y2K proportions.

Regulators with considerable muscle, like the European Union, have set their atomic alarm clocks, however, demanding that a solution to metallic five o'clock shadow be in place by July 1, 2006, when lead-laden electronics will be illegal for sale in member countries.

So stay tuned. And if your high-tech shaver fails, blame it on tin whiskers.


I looked around to get a feeling for how dangerous tin whiskers really are. Apparently, tin, zinc, and some other metals can form metal whiskers up to 1-2 mm long over the course of months to several years. Alloying (eg, with lead) is one of several ways to reduce but not prevent whisker formation.

In the Risks Digest, I see only two mentions to metal whiskers (and a third to ferret whiskers :-). So it appears that the problem is relatively rare (or perhaps rarely diagnosed/reported accurately).

Looking around, I found a article/presentation (appears to be on or after 2002) that focuses on the dangers of tin whiskers in military electronics and appears to be worth a close look. One thing that was disturbing was that a lot of electronics was being switched to pure tin and that many of the parts suppliers (the article claims one half of those surveyed) weren't aware of tin whisker formation. NASA, who "prohibits" the use/presence of pure tin surfaces still had "1-2% pure tin parts" enter their satellite systems at some point (date not specified).

The ecological dangers seem overrated especially when compared with lead-acid batteries. From the paper:

Note: In the EU starting in 2006 - Electronic Solder (0.49%) will be banned, but Lead Batteries (80%) will be exempt. Reason: "cars can not run without batteries but the electronics industry can manage without lead ." (Chart is based on Consumption) [chart came from "Advancing Microelectronics", Sept/Oct 1999, pg 29, vol 4]


Note: EU exempts lead acid batteries from the landfill, but prohibits consumer electronics from disposal. (Chart is based on Lead containing Discards as a Weight Percent) [EPA, 1998]

From the chart refered to in the second quote, consumer electronics seemed responsible for 4.4% of lead leachate in US landfills, but batteries were responsible for 48.1%.

This seems to me to be a gross imposition on the electronics industry without a good reason. If lead is really that bad, then they should regulate more sternly battery producers, who are the prime consumer of lead and producer of lead tainted waste.

I agree. What do you think their motives are to single out the electronics industry?

I think the electronics industry was just a target of opportunity. A considerable portion of the political side of the Green movement seems driven by ideology rather than practical considerations. Perhaps they need to demonstrate that they are "improving" the environment via imposing regulations on industry and commerce. Ie, a politician who does nothing may fall out of power.

Also glancing at the table of EPA contributors to lead leachate, I see three items ahead of consumer electronics, namely, batteries, CRTs, and glass/ceramics. The first two are virtually untouchable from a Green point of view because they already serve an ideological function. The lead-acid battery is still a decent choice for an electric car and for a storage system for home based power systems. Meanwhile the lead in CRTs (cathode ray tubes in TVs and computer monitors) shields millions of people from the CRTs' electromagnetic field radiation (including a small amount of soft X-Rays, I understand). I believe that the lead is required in CRTs to meet existing regulations on EMF emissions. The category of "glass and ceramics" may be regulated. It is only modestly larger than consumer electronics.

So politically, electronic devices are among the largest categories of lead sources that can be regulated more with relatively little consequence.

Moving to unleaded gasoline a couple of decades back did wonders for the environment. But I agree with Karl that at some point we have to ask whether removing all lead from circulation is either possible or desireable.

I think you hit the tin whisker on the head, Karl. I realize that we all have blind spots when it comes to our political idealology. One goal I have for 2005 is to examine mine closely. The EU's blind spot, however, could be extremely hazardous to the environment and the environmental movement. It would seem to me that in the long-term, dealing with the real dangers of lead from all sources would give environmentalists more credibility and elicit better cooperation. But maybe I'm just an idealist.

I guess the question is...what viable alternatives exist or can be developed in the near term? The EU's pending ban could actually be a good thing if it leads to a new set of solutions.

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