diff -rupNB --exclude='.*' a/VolumeRendering/vtkUnstructuredGridBunykRayCastFunction.cxx b/VolumeRendering/vtkUnstructuredGridBunykRayCastFunction.cxx
--- virgin_vtk/VolumeRendering/vtkUnstructuredGridBunykRayCastFunction.cxx	2009-02-17 17:25:03.000000000 +0000
+++ VTK/VolumeRendering/vtkUnstructuredGridBunykRayCastFunction.cxx	2009-09-10 15:37:33.000000000 +0100
@@ -545,6 +545,11 @@ void  vtkUnstructuredGridBunykRayCastFun
     }
   this->TriangleList = NULL;
   
+  // Delete TetraTriangles if it has been allocated before
+  // The triangles held by it should have also been in TriangleList so no
+  // need to "deep" clean
+  delete [] this->TetraTriangles;
+  
   // A temporary structure to reduce search time - VTK_BUNYKRCF_NUMLISTS small 
   // lists instead of one big one
   Triangle *tmpList[VTK_BUNYKRCF_NUMLISTS];