The mechanochemical decomposition of different chemicals such as 1,2,3-trichlorobenzene (TCB), monochlorobiphenyl (BP-Cl), and aromatic polyamide (aramid) was attempted by using a planetary mill with inorganic additives such as CaO. The ground products were characterized by different equipment, including ion chromatography (IC), gas chromatography (GC/MS), X-ray diffraction (XRD), Raman spectroscopy, and electron spin resonance (ESR). The dechlorination reaction reached almost 100% during prolonged grinding periods of time, and was accompanied by radicals, which play a significant role in the decomposition and its yield. One of the main components in the ground product was inorganic chloride, and its amount was found to increase with lengthier grinding time. Other components in the products were amorphous carbon and CaCO3. These findings should be useful for practical applications in the detoxication of many organic toxic substances. (C) 2004 Kluwer Academic Publishers.