diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
index b57bc02..99e5864 100644
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -5578,6 +5578,7 @@
 	PyDict_SetItemString(d, "error", PyExc_OSError);
 
 #ifdef HAVE_PUTENV
-	posix_putenv_garbage = PyDict_New();
+	if (posix_putenv_garbage == NULL)
+		posix_putenv_garbage = PyDict_New();
 #endif
 }