Definition

Halogen-free PCB materials contain minimal levels of chlorine, bromine, and other halogens, using alternative flame retardants. Halogens are restricted due to environmental concerns: when burned, halogenated materials can release toxic dioxins and furans. Halogen-free is defined by IEC 61249-2-21 as <900ppm chlorine, <900ppm bromine, and <1500ppm total halogens. Halogen-free laminates use phosphorus-based or nitrogen-based flame retardants. Many manufacturers offer halogen-free versions of standard materials (e.g., Isola 370HR is halogen-free).