diff --git a/Modules/Compiler/XL-CXX.cmake b/Modules/Compiler/XL-CXX.cmake
index 961cfee61..c4e4550dd 100644
--- a/Modules/Compiler/XL-CXX.cmake
+++ b/Modules/Compiler/XL-CXX.cmake
@@ -1,5 +1,9 @@
 SET(CMAKE_CXX_VERBOSE_FLAG "-V")
 
+# -qthreaded     = Ensures that all optimizations will be thread-safe
+# -qhalt=e       = Halt on error messages (rather than just severe errors)
+SET(CMAKE_CXX_FLAGS_INIT "-qthreaded -qhalt=e")
+
 SET(CMAKE_CXX_FLAGS_DEBUG_INIT "-g")
 SET(CMAKE_CXX_FLAGS_RELEASE_INIT "-O -DNDEBUG")
 SET(CMAKE_CXX_FLAGS_MINSIZEREL_INIT "-O -DNDEBUG")
diff --git a/Modules/Compiler/XL-Fortran.cmake b/Modules/Compiler/XL-Fortran.cmake
index cf9b2b657..17a3dd2dd 100644
--- a/Modules/Compiler/XL-Fortran.cmake
+++ b/Modules/Compiler/XL-Fortran.cmake
@@ -2,6 +2,10 @@ SET(CMAKE_Fortran_VERBOSE_FLAG "-V")
 
 SET(CMAKE_Fortran_DEFINE_FLAG "-WF,-D")
 
+# -qthreaded     = Ensures that all optimizations will be thread-safe
+# -qhalt=e       = Halt on error messages (rather than just severe errors)
+SET(CMAKE_Fortran_FLAGS_INIT "-qthreaded -qhalt=e")
+
 SET(CMAKE_Fortran_FLAGS_DEBUG_INIT "-g")
 SET(CMAKE_Fortran_FLAGS_RELEASE_INIT "-O")
 SET(CMAKE_Fortran_FLAGS_MINSIZEREL_INIT "-O")