Problems Implementing The Restriction of Hazardous Substances

Tag : tin sheet

If we are to believe the Wikipedia article "Restriction of Hazardous Substances", it hasbeen a big success. However, Wikipedia articles need not have any reliability as they reflect the viewsof the last one to edit them, and that can be anyone. It might beuseful to look at the facts regarding a very controversial aspectof this directive. The directive required that solder contain lessthan 0.1% lead. This simple directive was issued withoutconsideration of all of the consequences. The proof of thatstatement is that there is NO evidence that all the consequenceswere considered. Even before the 2006 EU ban, most manufacturersmade the switch in advance due to shelf-life of products and needto work out problems with the new material. There have beenproblems. Serious problems.
Often, the removal of lead from solder has been by replacing itwith SAC305 which is 96.5 % tin, 3.0 % silver and 0.5% copper. Theincreased in tin content will increase the use of tin by about11,000 tons a year. The world production of tin is roughly 300,000tons. This 3 or 4% increase is small but in context of estimates ofthe exhaustion of the world's tin deposits in 20 -40 years, it isworth considering. ("How Long Willl it Last" {May 26,2007} New Scientist 194 :38-39)
Another part of the problem with removing lead from solder is theloss in reliability of electronic devices. Lead solder made tough,flexible (not brittle) joints that were resistant to mechanicalshocks. None of the replacements have anywhere as good mechanicalproperties. Dropping a cell phone accidentally is common, but nowit is much more likely to die.
Removing lead from solder has brought a new problem into play. Tinwithout lead grows whiskers, crystalline filaments. These filamentscan and do produce random short-circuits. They have destroyed billions of dollars worth of satellites . They have created incidents at nuclear power plants including afalse shut-down command at the Millstone nuclear reactor atMillstone, Connecticut. NASA and other agencies have documentedmany cases where tin whiskers have been responsible for failure ofelectronic equipment. However, most electronic equipment failure isjust accepted as a matter of fact and no effort is made to pinpoint the actual cause of failure. In truth, many failures are theresult of mechanical shock or tin whiskers. NASA scientists haveverified this but manufacturers prohibit a public release of theinformation. The manufacturers don't want you to know.
The NASA website http://nepp.nasa.gov/whiskers gives scientific facts about what we know and what we don't knowabout them or what causes them. The bottom line is that no one fully understands what causes them. We do know that a few percentlead will prevent them. At the present time, in the absence of tin,we can not estimate when tin whiskers will form. They might form ina few months and in other cases can take ten or more years. Theyadversely affect the reliability of electronic devices. Theirrandom behavior has made research very difficult.
It is well established that lead is harmful when ingested. It mightbe argued that any lead in the environment is bad. Eleven thousandtons is a lot of lead. However, 11,000 tons compared to 3 or 4million tons of lead used is rather small, About 88% of lead isused in storage batteries, 3% is used for ammunition, glass andceramics use 3%, casting metals about 2% and sheet lead about 1%.Solder used to consume about 0.5 %. That's all: one-half of onepercent. The havoc caused by using one-half-of-one-percent lesscannot be justified by any stretch of the imagination.
Most of the lead ingested by humans originated from leadedgasoline. Leaded paint is still a major source of lead for humans,particularly that coming from China. Several Ayurvedic medicineshave large quantities of lead. Some forms of cosmetics have a lotof lead. There was a time when tinned cans were soldered. Thisresulted in contamination of the food. Even today, there is somelead in the tin used to plate tin cans and this leaches into thefood. Canned pineapple, fruit cocktail and canned tomatoes havelead levels in excess of the legal maximum of fifty parts perbillion, and the food manufacturers know this. Why is nothing beingdone about lead in our food, and yet this witch-hunt for lead inelectronics? Who eats their computer?
There is a published account of children getting lead from leadfishing sinkers stored on the floor on which they played. Workersworking with lead are known to accumulate lead in their bodies. Theproper design of the work place should greatly reduce this. Thecost of properly designed work spaces is trivial compared to the$38 billion and climbing cost of removing lead from solder. ( Technology Forecaster Inc. )

Lead poisoning is difficult to diagnose. Most commonly, diagnosisis done by measuring the lead content of the blood. It might be ofslight interest that in most of the cases of lead poisoning due toherbal remedies described in PubMed, the doctors are outside Indiadescribing patients who have taken Indian medicines.
To summarize, adding lead back into solder will greatly increasethe reliability of electronic devices. The effect on humans issmall compared to the other sources of lead. The effect on humanscan be mitigated by properly designed work spaces.
What should be done? The first thing that must be done is therecognition that the removal of lead from solder was unwise. It wasa mistake taken without considering the total costs andconsequences. In the United States, it might be possible to requirean Environmental Impact Report before any lead-free devices couldenter the country. I do not know that any was ever done beforeelectronics without lead were imported. That was clearly a mistake.It should be remedied now.