diff --git a/modules/util/util.py b/modules/util/util.py
index 593b6b213443b2da3e05a9f4d588c1a4e88ade57..c617978715fb62d6b9400311729d804a0df58593 100644
--- a/modules/util/util.py
+++ b/modules/util/util.py
@@ -55,7 +55,11 @@ ds_range.update({'cloud_fraction': 'actual_range'})
 
 def get_fill_attrs(name):
     if name in ds_fill:
-        return ds_fill[name], None
+        v, s = ds_fill[name]
+        if v is None:
+            return v, '_FillValue'
+        else:
+            return v, None
     else:
         return None, '_FillValue'