Hexachlorobicyclo[2.2.1]hept-5-ene-2,3-dicarboxylic Acid is a novel flame retardant (NFR) which has also been observed as a toxic and environmental pollutant. Chlorinated Reactive Flame Retardant Intermediate Environmental toxin on US EPA Toxic Release Inventory list (TRI) list. Molecular Formula: C9H4Cl6O4 Molecular Weight: 388.84