An experimental investigation of the influence of inhibitors of various chemical natures on flammability limits in mixtures H-2+ oxidizer (O-2+ N-2)-Suppressant (C2HF5; CHF3; C4F10; inhibitor AKM, which is a mixture of olefins) was carried out. Compositions of N2 and 02 with elevated (25vol%) and reduced (15vol%) oxygen concentrations and air were used as oxidizing atmospheres. Experiments were done at room temperature and atmospheric pressure. Flammability limits were determined in a closed vessel of volume of 4.2 dm(3) (internal diameter 20cm). Mixtures were prepared immediately in the preliminary evacuated reaction vessel by partial pressures. The mixtures were ignited by an electrical spark of energy near 1 J in the center of the reaction vessel. A flame propagation was detected by a pressure transducer. Twelve flammability curves were measured, which allowed to compare effectiveness of the inhibitors at various oxygen contents in the atmosphere. A qualitative analysis of the obtained results was done, which showed an important role of an inhibitor regeneration. (C) 2007 Elsevier Ltd. All rights reserved.