Abstract: Apparatus is provided for giving an early warning of the occurrence of breakout of molten metal from a partially solidified cast strand downstream from a continuous caster mold. The apparatus includes a hollow body (preferably tubing) located adjacent to the strand. A source of fluid connected to the body is adopted to maintain substantially constant pressure of the flue therein. A monitoring device provides a signal when a significant drop in fluid pressure occurs in the body, so that an early warning of the breakout of molten metal and resultant fusion and opening of a hole in the wall of said body is provided.