AbstractThe objective of this study was to determine the effects of certain fire-retardant chemicals on the combustion resistance of high-density fiberboard (HDF). Borax (BX), boric acid (BA), ammonium polyphosphate (APP), and alpha-x (AX) were added into the fibers made from 50% scots pine (Pinus sylvestris L.) and 50% beech (Fagus orientalis Lipsky) woods at 3%, 6%, and 9% levels based on oven-dry fiber weight. HDF panels were produced in 6.5 mm thickness. HDF panels’ combustion behavior was explored. To detect combustion resistance, the panels were tested according to the ASTM-E 69 and thermogravimetric analysis (TGA) tests. It was determined that fire-retardant (FR) chemicals enhanced the combustion resistance of the panels to varying degrees. As a result, the FR chemicals’ type and concentrations are effective for determining the combustion resistance of HDF panels.