Under our current living conditions, the use of flammable materials, such as plastics, composites, and foams, in building envelopes and interior furnishings has increased significantly. Therefore, fire presents a serious health hazard, and various techniques have been developed to mitigate this risk. In addition to technical solutions, hundreds of chemicals are used today for fire protection. Notably, halogenated compounds, including brominated and chlorinated flame retardants and phosphorus compounds, were used in large quantities over decades, resulting in an exposure risk to humans. These are known as additive flame retardants, which are not chemically bound to polymers and can therefore be released into the environment through leaching, evaporation, or abrasion from products during production and processing. Some groups of flame retardants were chemically stable, persistent in the environment, and had a tendency to bioaccumulate, raising toxicological concerns. Thus, a brief description of the chemical-physical characteristics and usage patterns of various flame retardants, their primary health risks, and toxicokinetic properties, along with references to further scientific literature, is provided. The main objective is to detail their occurrence in human matrices, such as blood, urine, and breast milk. For this reason, detailed information is provided on polybrominated diphenyl ethers (PBDE), polybrominated biphenyls (PBB), organophosphate flame retardants, hexabromocyclododecane (HBCDD), and emerging brominated flame retardants like tetrabromobisphenol A (TBBPA), 1,2-bis-(2,4,6-tribromophenoxy)ethane (BTBPE), 2-ethyl-1-hexyl-2,3,4, 5-tetrabromobenzoate (EH-TBB), bis(2-ethyl-1-hexyl)tetrabromophthalate (BEH-TEBP), decabromodiphenylethane (DBDPE), and tetrabromoethylcyclohexane (DBE-DBCH).