diff --git a/Event/NavFourMom/NavFourMom/ATLAS_CHECK_THREAD_SAFETY b/Event/NavFourMom/NavFourMom/ATLAS_CHECK_THREAD_SAFETY
new file mode 100644
index 0000000000000000000000000000000000000000..7c36fcc2d6e0a1ae2726c94b553cc091b1df0a4d
--- /dev/null
+++ b/Event/NavFourMom/NavFourMom/ATLAS_CHECK_THREAD_SAFETY
@@ -0,0 +1 @@
+Event/NavFourMom