Graphical abstract

Flame retardants are a class of chemicals utilized to provide fire safety performance to other materials, structures, and devices used in modern society. These chemicals are highly varied in molecular structure and chemistry and work by one of the following three main mechanisms: vapor‐phase combustion inhibition, endothermic cooling, or condensed‐phase char formation. The chemicals in use today fall into seven main chemical groups including halogenated, phosphorus based, mineral fillers, nitrogen based, intumescent materials, inorganic materials, and polymer nanocomposites. In this article, how flame retardants are used, how they work, and when to use them is discussed. From the article, it will be clear that flame retardants are chemicals employed to provide fire protection for specific materials in specific fire risk scenarios. Specifically, while the term “flame retardant” can cover a wide range of materials and chemicals, not all materials called flame retardants are effective in all materials and against all fire threats. Each flame retardant chemical must be tailored for its end use, and in this article, the criteria for flame retardant selection and use will be discussed in a general manner. This article serves as an overview of flame‐retardant technology from how they are used today, what chemistries are used, and what the future of this technology may be. The article is comprehensive in scope about what this chemical technology is, but cannot provide all of the essential details for proper use of these materials in end‐use fire safety applications. Still, guidance is provided in the article to help the reader to understand the breadth of the technology and where to go to learn more, or how to engage intelligently with fire safety engineers and fire safety scientists to develop fire‐safe materials.