Toxic Chemicals in Electronics

Article By : Michael Kirschner

Selecting a part based on its electronic parameters alone risks having to find a replacement later and perhaps even recalling a product.

When you design (your part of) an electronic product, particularly if you’re an electrical/electronic engineer (EE) like me, you don’t tend to think about much other than the functional and parametric requirements of the specific challenge you’re trying to solve.

The supply base understands this: an electronic component datasheet tells you what it does, how it does it (if necessary), and includes a raft of parametrics specific to the purpose of the device and what is important to specifiers like you. These datasheets, however, rarely if ever indicate what the item is made of, even if it’s not a trade secret. This information is generally not considered relevant to its form, fit, or function.

And even if they did publish it, EEs wouldn’t care or, in most cases, know what to do with it. Plenty of EEs get through their careers not having to understand much more chemistry than the fact that copper conducts electricity and heat better than iron.

Mechanical engineers do need a decent understanding of chemistry, though they normally focus, again, on functional and parametric requirements.

The unfortunate fact is that, just like the wrong functionality or parametric value can result in the elimination from consideration of a component or material, so can the wrong substance in its composition. If you’re not looking for it up front at the same time you’re looking at functionality and parametrics, the risk of having to find a replacement later on during your product development process and potentially delaying time to market, or even having to pull the product from the market, increases.

Deep familiarity with regulatory and market requirements is now necessary; if your company doesn’t have this expertise – and I would not recommend that it be left to design engineers; that’s not their expertise – I recommend investing in it already.

While you may be familiar with RoHS and its handful of restricted substances, a boatload of other similar regulatory requirements exist in your markets. I won’t go over those here; I cover them in another column. What I do want to point out here is that this is not a static issue; substances used in electronic products are constantly being identified for disclosure, restriction or outright ban in one market or another around the world. Here are some that are in-process now that may be in your products:

  1. An ultraviolet absorber used called UV-328 is commonly used in plastics and on LCD touchscreens. UV absorbers are used to slow the degradation of plastics due to UV light. This is currently up for an international ban by the Stockholm Convention. UV-328 is also on the candidate list of substances of very high concern (SVHCs – it has been on the list for six and a half years) so it’s flagged for action by the European Commission, but the Stockholm Convention will probably beat them to the punch now.
  2. In 2015 the European Union RoHS Directive added four phthalates to the list of restricted substances. Periodically they add new substances to this list, maintained in Annex II of the Directive. A process completed last year by consultants identified two commonly used substances for restriction: tetrabromobisphenol-A (TBBP-A), which is a flame retardant used in printed circuit boards and certain hard plastics, and medium-chain chlorinated paraffins (MCCP), which is a flame retardant and plasticizer used in PVC cable sheathing. The European Commission, which is responsible for RoHS, usually, but not always, agrees with the consultant’s assessment; we are still awaiting their decision.
  3. When the commonly used flame retardant decabromodiphenyl ether (DecaBDE) was finally restricted by RoHS back in 2008, many in the industry moved to a drop-in replacement called decabromodiphenyl ethane (DBDPE).

You can see just how similar these molecules are. They are so similar that, in fact, the Canadian government has determined that DBDPE should be restricted too. Expect that to happen within the next year.

  1. Next up, per- and polyfluoroalkyl substances, or PFAS. These substances have many virtues; they reduce friction, impart water- and oil-resistant properties, and, as Teflon® (PTFE) insulation, have excellent thermal and electrical characteristics in wiring insulation. However, they are toxic and, because the carbon-fluorine bond is the strongest known to organic chemistry, they do not break down in the environment, leading to their (colloquially) being called “forever chemicals”. The European Chemicals Agency, the US Environmental Protection Agency, and the US House of Representatives have processes or proposals in place that will, in time, result in widespread bans of most if not all of this rather large class of chemicals.

And the beat goes on. Looking ahead and taking a risk-based approach to material and component selection based on the potential for future regulation is simply good business practice today.

Right now your (often far-upstream) chemical suppliers have near-zero risk for providing toxic substances to you for use in your products (unless they get sued for polluting the environment while manufacturing substances for your product; watch the film Dark Waters, for instance). They get the opportunity to sell you a replacement once their substance gets banned but are not culpable for selling a substance that cost your company time and money to replace because a government banned it. Avoiding a regrettable substitution, which is replacing one banned substance with another that will just get banned in the future (like DecaBDE and its replacement DBDPE), should be part of a manufacturer’s product lifecycle management process.

This article was originally published on EE Times.

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