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Halogens and Halides: What You Need to Know

Part 1 of 2 — What They Are and Why They’re a Concern

26 October 2018

By John Vivari

As halogen-containing substances face increasing scrutiny by the European Union and several nongovernmental organizations (NGOs) due to their known and suspected risks, it’s important to understand what changes you should expect if required to stop using them in your electronics manufacturing process.

In part 1, we’ll talk about what halogens and halides are and why they’re a concern. Then we’ll talk about any changes you may need to make to comply with a potential ban of using these materials.

Snip it of the Periodic Table

What are Halogens and Halides?

When examining the periodic table, you will find that halogens are the electronegative elements in column 17, including fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At).

Halides are chemical compounds that contain halogens. Halides are present in nature with some — namely salts and acids — being essential to human life. Halides can be found in minerals, animals, and plants. The best-known halide is NaCl: table salt.

Why are Halogens a Concern in the Electronics Industry?

While some halogen-containing substances or halides are safe, there are some that have raised suspicions as being toxic and carcinogenic. In the electronics industry, this can be a concern as some of these materials are used in manufacturing.

For example, we know that chlorine is used to keep drinking water safe by killing off unwanted bacteria. It is not harmful to humans in such a low concentration. However, concerns arise when chlorine gas is released into the air.

The use of nonbrominated epoxy resins can leave chlorine as a residual material during the production of circuit boards. Concentrations are typically below 100ppm, but the concern lies in the fact that too much chlorine may be dangerous to humans and the environment.

Other sources of halogens in circuit boards include fiberglass sizing, epoxy curing agents and accelerators, resin wetting and de-foaming agents, flux residues, and contamination from handling. In the broader category of “electronics,” many plastics, papers, coatings, sealants, lubricants, and adhesives are added to the list of sources.

What Solutions are Being Discussed?

The main issue involving halogens and the electronics industry is the unregulated disposal of materials by incineration. Uncontrolled burning can lead to the unnecessary release of halogens into the environment due to the byproduct production of dioxins and furans. Because the effects of halogens on the environment are still being researched, it is difficult to determine if the release of these halogens can cause long-term effects. The big question is whether the industry will soon be facing new regulations requiring certain ways of disposing materials.

Luckily, the technology is currently available. Some facilities are already using halogen-free processes in their production. Modern incineration technology has virtually eliminated concerns over dioxin and furan production from waste disposal in modern facilities.

What does that mean for facilities that do not have the technology yet?

Based on previous regulation processes, the probability of halogen regulations is high. It might be time to start planning for when regulations are in full force.

In our next article, we will discuss the need for halogen-free materials and the differences between them and what is regularly used now. We will delve further into the concerns of halogens and halides to better understand whether changes will become necessary or processes will remain unregulated.

For more in-depth information on this topic, be sure to check out this Halides and Halogens white paper.

Or if you’d like to learn about Nordson EFD’s halide-free or zero-halogen flux and solder paste, contact us at

Photo of John VivariAbout John Vivari

John Vivari is the Global Product Line Manager for Solder products at Nordson EFD. He uses his expertise in fluid dispensing and solder paste technology to assist customers in the development of precision dispensing, printing, and reflow processes. John has more than 20 years of electronic design and assembly experience. He joined Nordson EFD in 2001.

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