When shopping for components it's common to find a lead-free or RoHS-compliant version of the part along side one that is not. Under what circumstances does it matter that I chose exclusively lead-free or RoHS (or whatever other lead-free designation is out there) parts? What would motivate me to pick a lead-free part over a cheaper non-lead free part?

On a side note, some explanation of what all this lead-free business is about would be interesting to me.

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    \$\begingroup\$ Lead is a heavy metal, it is not good for you to handle or ingest heavy metals. RoHS is an EU directive that bans those materials in products. When I did work with devices entering cattle we were required by the FDA to use lead free products. When will it affect at home use, not at all, unless you are dealing with lead free solder. \$\endgroup\$ – Kortuk May 5 '11 at 14:03
  • \$\begingroup\$ lead is very bad. I heard somewhere that now we (usa) doesnt have the mental instability problems and other issues in the younger generation that has grown up without lead in the air. From an engineering perspective where you would choose to use it or not has to do with selling the product. If you want to make a product and sell it choose lead-free now and just get used to doing that. If this is a hobby project, it is your choice, take the leaded stuff its probably cheaper (and more reliable). but expect not to be able to thrown that item in the trash can in the future \$\endgroup\$ – old_timer May 5 '11 at 17:41

Aside from the RoHS stuff mentioned, in our lab we use lead free solder for high temperature circuit work, we tend to operate diodes and JFETs up to around 450degC and we've found leaded solder can't take the heat. Of course without the lead the solder is harder to work with but the result is that we can test circuits at high temperature without having to make mechanical joins between components, which is the alternative.

Oh, and although you can't use leaded solder in Europe for commercial products you can in military stuff - I think the theory is that military people don't tend to lick circuit boards but there is always the risk that a toddler will in consumer stuff :-)

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    \$\begingroup\$ maybe that the device the military is using is more dangerous then the risk of touching lead? I still thought they tried not to restrict technology by allowing devices that could not exist otherwise, like some LEDs, to use heavy metals. \$\endgroup\$ – Kortuk May 5 '11 at 14:22
  • \$\begingroup\$ I'm not sure, but that sounds reasonable - especially given that the heavy metal inside LEDs is likely encased in plastic so it would be difficult to touch. \$\endgroup\$ – SimonBarker May 5 '11 at 14:28
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    \$\begingroup\$ so would the lead inside an IC, I think they are trying to avoid letting heavy metals into landfills and the environment. Finding the reason behind legislation though, good luck. \$\endgroup\$ – Kortuk May 5 '11 at 14:53
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    \$\begingroup\$ I believe Military and aerospace applications are exempt because the reduced reliability of lead-free solder connections would be unacceptable there. If someone's television set fails because the lead-free connections developed faults, that's a good thing--means the guy has to get a new television set. But if a plane falls from the sky, that's not so good. \$\endgroup\$ – supercat May 5 '11 at 16:05
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    \$\begingroup\$ One major reliability worry from RoHS is Tin Whiskers. Since the lead in solder is usually replaced with more tin, this can be a major issue related with shorting things out. nepp.nasa.gov/whisker/background \$\endgroup\$ – W5VO May 5 '11 at 18:55

RoHS (Restriction of Hazardous Substances Directive) covers a number of hazardous substances, not just lead. Google RoHS for a list.

You can not sell an electronic product in Europe if it contains any of the listed toxins. It seems likely that other parts of the world will follow suit.

The main challenge with RoHS is that you can not use solder that contains lead. Lead-free solder has a higher melting point and is generally a bit more tricky to work with.

On the bright side, you are less likely to cause lead poisoning to yourself or anyone else manufacturing or recycling your product :-)

EDIT: The general idea is that these toxins tend to concentrate in places like landfills. Sooner or later this stuff returns to bite you through fires, leaks etc.

The RoHS directive is not an absolute ban, it specifies the max concentration. You can for example have 0.1% lead in your product. Industrial products may not require RoHS compliance, you can for example use NiCd batteries in medical equipment even if it is banned for consumer use. But the batteries have to be brought in to recycling stations after use.

As an individual you are welcome to lick lead all day long or to import non-compliant products for your own use. You can use solder containing lead as long as you don't sell what you make.

  • \$\begingroup\$ I thought many different components like LEDs often had a waiver not requiring RoHS compliance, do you know if this is true? \$\endgroup\$ – Kortuk May 5 '11 at 14:16
  • \$\begingroup\$ @Kortuk Yes, there is a list of exemptions including color LEDs that use phosphors containing cadmium. Products that does not have a feasible substitute can get a time limited exemption for 5-10 years it seems. \$\endgroup\$ – morten May 5 '11 at 15:38
  • \$\begingroup\$ Strange that LEDs using cadmium would be allowed, but CdS (cadmium sulphide) cells - arguably the simplest light sensor - are not. \$\endgroup\$ – Thomas O May 5 '11 at 20:56
  • \$\begingroup\$ Well, I guess it makes sense... There are alternatives to CdS based sensors readily available. Non-Cd phosphors are becoming available for LEDs as well, so it is possible that LEDs won't be exempt after 2014. \$\endgroup\$ – morten May 6 '11 at 11:05

These are the substances prohibited by the RoHS legislation (copied from the UK Government leaflet):

RoHS restricts the use of mercury, lead, hexavalent chromium, cadmium and a range of flame retardants notably polybrominated biphenyls and polybrominated diphenyl ethers.

  • \$\begingroup\$ Why the downvote? \$\endgroup\$ – Leon Heller May 10 '11 at 16:41
  • \$\begingroup\$ Good Question. I upvoted because i found no reason to downvote \$\endgroup\$ – RCProgramming Oct 16 '11 at 20:07

As others have already pointed out, RoHS requirements generally forbids the use of components with hazardous materials (with some exceptions made for batteries and other specialty components where alternatives do not exist).

As a manufacturer of your product, you'll need to certify your product is RoHS compliant (amongst many other regulatory and industry requirements like emissions, safety, recyclability) in order to satisfy your customers and (in increasing number of markets) to be legally sold. Because of this, the entire "supply chain" from the components, to the printed circuit board, to the board assembly (i.e. soldering) will need to be documented as being RoHS.

Not being "RoHS" doesn't necessarily mean that the item contains a hazardous substance. Sometimes, the products are given the RoHS designation to confirm their process compatibility with no-lead manufacturing. Because lead-free solder has a higher melting point, the components must also withstand higher temperatures during board assembly.

  • \$\begingroup\$ to be legally sold in the EU. Other regions (notably including most of the USA) have less stringent requirements for electronics. \$\endgroup\$ – Kevin Vermeer May 5 '11 at 16:07
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    \$\begingroup\$ For now. But the EU is a large market already; and California already has the RoHS law as well - and as California goes, so goes the rest of the U.S., eventually. \$\endgroup\$ – Toybuilder May 5 '11 at 17:13
  • \$\begingroup\$ California only implements a small subset of the RoHS directive. Also, California does a lot of weird stuff - I hope the rest of the US doesn't follow them in every area... \$\endgroup\$ – Kevin Vermeer May 5 '11 at 18:18
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    \$\begingroup\$ @reemrevnivek - well, it's certainly been said of music and cars... and products from a certain company in Cupertino, California! :) Thanks for pointing out that California's restriction only applies to a small subset (for now). I do believe that in the long term, the RoHS rules will harmonize globally like safety rules, and so RoHS will be universal. \$\endgroup\$ – Toybuilder May 5 '11 at 18:46

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