Thanks a lot ROHS. Which is more likely to kill people, poisoning from trace amounts of lead buried in your electronics, or vehicles that careen out of control due to the growth of tin whiskers? The law of unintended consequences wins again.

Toyota accelerations revisited—hanging by a (tin) whisker
Rick Demeis, EE Times -- EDN, January 10, 2012

Several accelerator pedal position sensors had tin whiskers that could cause short circuits. A NASA paper delivered at the International Tin Whisker Symposium last year reported on tin whisker growth in Toyota accelerator pedal position sensors that, depending on pedal rate of movement, could lead to unintended acceleration.

The whiskers were found in a "failed" sensor from a 2003 Camry and at least two other similar units that did not malfunction. The sensor in question was used on the Camry from 2002 to 2006 model years, and the specific Camry with the defective sensor (which was furnished to NASA) had 82,000 miles on it. The vehicle owner reported the car as "undrivable," with throttle response as: "I couldn't get any 'gas', and then the car would jerk forward at a rapid rate." The sensor had at least 17 whiskers in it, only one of which shorted contacts.



While the inspected sensors noted above could be typical of the entire lot, these incidents of whisker growth and shorting give cause for safety concern across the industry.

The NASA paper gives further insight by detailing tin whisker physical behavior as well as outlining guidelines and methods of detecting whiskers. But rather than summarize the report here, readers can access the easily-read, but complete, 30-page NASA presentation by clicking here.

Even with ROHS exemptions, it's been impossible to get components with non-lead-free plating. There's just not enough volume in aerospace, medical devices, and stuff that will never be sold in the EU for the component manufacturers to economically justify the production of components with lead when the vast majority of what they make has to be lead-free.

You can still use leaded solder on them, but it's not good enough to eliminate all the problems introduced by the lead-free plating. The only alternative is to have a third party replate the components at huge expense, and a risk of reduced reliability thanks to the extra handling and thermal cycles.

Not to mention the environmental impact of more electronics ending up scrapped earlier.

We must save people from the dangers of lead exposure, not matter how many are killed in the process.

A German crane and hoist manufacturer has moved heavily to printed circuits in crane controls in the last few years.  We see mysterious error codes, the manufacturer claims to have never heard of the code, then recommends changing out about $2000 worth of boards to see if that makes the problem go away.  (Even if the original product cost less than that.)  I am aware of down time, but not weird failures leading to accidents.

I wonder if tin whiskers are at fault.


+1 on your new band name.  I suggest an image of the Tin Man with 5 o'clock shadow.

Just about every electronic or electrical component has tin whisker issues.
Radar components with their high voltages have a lot of problems with arcing inside the frames and between solid state chip leads.

Bender?