diff --git a/openmc/statepoint.py b/openmc/statepoint.py
index 19aa3dbaf..d5dd7bc1e 100644
--- a/openmc/statepoint.py
+++ b/openmc/statepoint.py
@@ -1,6 +1,8 @@
 import sys
 import re
 import os
+import warnings
+
 import numpy as np
 
 import openmc