What does RoHS Compliant mean? RoHS = Restriction of Hazardous Substance Directive
Here is the European Union WEEE directive that started it all. If you've seen the trash can icon with an X imprinted on an electronic device, you've seen this directive in action. Basically it is a reduction in lead and other harmful materials in electronics and how these products are disposed of. As of July 1st, 2006 many of the electronic products being sold in the EU must be RoHS compliant. There are exceptions including electronics that fall into the "Control & Monitoring Equipment" which many SFE products can be described as.
While the US has no legislation on use of lead in the manufacturing of electronics, we work hard to keep up with the rest of the world. Becoming lead-free was a huge pain, but we feel it's important to limit our footprint on the world. So the ICs and the components on RoHS products produced by SFE are lead-free, the solder and solder paste that is used during construction contains no lead, and the printed circuit boards (PCBs) are produced in such a way to have no lead or mercury, and some fun chemicals like polybrominated diphenyl ethers are extremely limited.
So if you see a product with this symbol, you'll know the board, components, and soldering techniques are all lead-free, RoHS compliant, and a little less harmful for you, me, and the earth.
If you'd like to learn more, checkout Wikipedia on RoHS.