[en] A summary is given of work undertaken to assess containment materials for the disposal of high level vitrified waste under geological disposal conditions. Corrosion rates of carbon steels, measured in long-term immersion tests with granite and bentonite backfills, range between 18 to 30 μm yr^-1 at 90 deg C, 10 to 24 μm yr^-1 at 50 deg C and 1 to 10 μm yr^-1 at ambient temperature. These rates are too high to be sustained by water reduction or oxygen diffusion and are probably caused by a more rapid oxygen transport process involving convective flow in the test tanks. Using improved electrochemical kinetic data the updated mathematical model predicts a steady corrosion rate of approx. 65 μm yr^-1 for carbon steel with a bentonite thickness > 10 mm. This is a pessimistic value since no account has been taken of the partially protective layer which in practice develops on the metal surface. Experimental studies indicate that maximum pit penetration after 1000 years will be < 30 mm. The results support the view that under granite or argillaceous disposal environments a carbon steel overpack thickness of 100 mm should be sufficient to prevent both general and localised corrosion penetration over a 1000 year period. (author)