Halogens are different than halides. A halide is a halogen that has collected an additional electron and has become ionic. Halides are associated with reliability issues in electronics when left uncontained.
For the most part, halogenated compounds are found in printed circuit boards, solder masks, mold compounds, connectors, cable insulation and wiring conduit. They are used because they offer excellent thermal resistance properties at relatively low costs. Halogens can also be used as raw materials in certain PCB assembly materials to help the activators keep working as the process temperature increases (as with Pb-free processing). These halogens are part of compounds which are present in far smaller quantities than in boards or components.
Using assembly materials products that have no halogens in their original formulation is the ideal way to eliminate the materials as possible halogen sources. Realizing the many different sources of halogens and the minimal environmental impact that low levels present, most organizations have adopted the levels developed by the International Electrochemical Commission (IEC) as acceptable in their final assembled product.
These levels are:
<900 ppm chlorine
<900 ppm bromine
<1500 ppm total halogens
*ALPHA® ZERO Halogen products have no intentionally added halogens in their formulations. Others listed above are Halogen-free, per the guidelines published in the following industry standards: JEDEC, IEC-61249 and JPCA-ES-01-1999.
IPC® Association Connecting Electronics Industries
Intel® Lead-Free and Halogen-Free Products