diff --git a/cmake/Compiler-GNU.cmake b/cmake/Compiler-GNU.cmake
index 1089e73f1..b9a7406dc 100644
--- a/cmake/Compiler-GNU.cmake
+++ b/cmake/Compiler-GNU.cmake
@@ -131,8 +131,10 @@ set (DEBUG_FLAGS "${DEBUG_FLAGS} -fcheck=all")
 set (DEBUG_FLAGS "${DEBUG_FLAGS} -fstack-protector-all")
 # Inserts a guard variable onto the stack frame for all functions
 
-# Detect memory leaks
-# -fsanitize=address
+set (DEBUG_FLAGS "${DEBUG_FLAGS} -fsanitize=undefined")
+# detect undefined behavior
+# Additional options
+# -fsanitize=address,leak,thread
 
 #------------------------------------------------------------------------------------------------
 #  precision settings
diff --git a/src/phase_mechanical_plastic_nonlocal.f90 b/src/phase_mechanical_plastic_nonlocal.f90
index e4e008fab..2ceaea7e2 100644
--- a/src/phase_mechanical_plastic_nonlocal.f90
+++ b/src/phase_mechanical_plastic_nonlocal.f90
@@ -1819,7 +1819,7 @@ subroutine storeGeometry(ph)
 
   integer, intent(in) :: ph
 
-  integer :: ip, el, ce, co
+  integer :: ce, co
   real(pReal), dimension(:), allocatable :: V