NOVELTY - Method for the safe operation of a continuously operated, heterogeneously-catalyzed, gas-phase partial oxidation of at least an organic compound in a reactor using molecular oxygen as oxidizing agent, under conditions of heterogeneous catalysis involves measuring the concentration of selected components of the feed gas to prevent the danger of explosion. The gas is subjected to pressure fluctuations to correct the measurement.    USE - The invention deals with a method for heterogeneously catalyzed, gas-phase partial oxidation of at least an organic parent compound, preferably oxidation of propylene and/or propane to acrolein and/or acrylic acid.    ADVANTAGE - The method prevents the danger of explosion during the feeding of feeding gas into the reactor, so that the method is safe. The method is continuous (all claimed) and economical.    DETAILED DESCRIPTION - Method for the safe operation of a continuously operated, heterogeneously-catalyzed, gas-phase partial oxidation of at least an organic parent compound in a reactor, whose feeding gas mixture stream besides the organic parent compound(s) to be partially oxidized and molecular oxygen as oxidizing agent, comprises of at least a dilution gas, which exhibits an essentially inert behavior under the conditions of the heterogeneously-catalyzed, gas-phase partial oxidation and which is produced by the combination of at least two different initial streams, where under inclusion of the online measurement of the concentration of selected components in the feeding gas mixture stream, or in initial streams producing the feeding gas mixture stream and/or in the product gas mixture stream, it is prevented that the reactor is fed with a feeding gas mixture stream that cannot be controlled with respect to the danger of explosion or otherwise; for online measurement, a partial stream of the gas flow to be analyzed in each case is continuously fed into a measuring chamber of an analytical device and during the measurement, the partial stream of the gas flow is fed out from the measuring chamber of the analytical device into a discharge atmosphere; the gas flow and/or the discharge atmosphere are subjected to pressure fluctuations, so that the influence of pressure fluctuations of the gas flow and/or the discharge atmosphere on the measured pressure in the measuring chamber in the analytical device and thus on the measurement result (a) is computationally corrected, and/or (b) is minimized by constantly regulating or adjusting the measured pressure, irrespective of the pressure of the gas flow and/or of the discharge atmosphere by means of a pressure control mechanism.