Abstract: Method for treatment of fluid hazardous, organic waste materials, where a plasma of 2000-5000° C. temperature is generated by means of an electric arc in a plasma generator, the plasma torch is directed into a reactor, the reactor consists of three zones (4A, 4B, 4C), the plasma torch being introduced downwards into the uppermost first zone (4A), the fluid waste (1) being sprayed into the plasma torch in the first zone (4A), where it is heated to a temperature range of 1300-1600° C., the mixture of the plasma and the waste is introduced into the second zone (4B) of the reactor, where an oxidizing material is added (5) to the mixture, the combustion gas produced in the second zone (4B) is then led into the third zone (4C) of the reactor, where it is cooled rapidly by water spraying to a temperature range of 120-160° C., the cooled combustion gas is removed from the third zone (4C) of the reactor is led into a cooler.