[en] The D0 solenoid was shown to be completely safe when deliberately quenched without a protection resistor in factory trials at Toshiba. In the tests the power supply was turned off shortly after the onset of the quenches. In this note an examination is made of the consequences to be expected if the power supply fails to turn off after the onset of a quench. The quite extreme assumption of simultaneous failure of the magnet power supply to switch off and the dump switch to open in the event of a magnet quench is seen to be completely harmless to the magnet.