diff --git a/toolkit/components/contentprefs/ContentPrefService2.jsm b/toolkit/components/contentprefs/ContentPrefService2.jsm
index 68c416c49942..f6c3866fdcb5 100644
--- a/toolkit/components/contentprefs/ContentPrefService2.jsm
+++ b/toolkit/components/contentprefs/ContentPrefService2.jsm
@@ -654,8 +654,10 @@ ContentPrefService2.prototype = {
   },
 
   destroy: function CPS2_destroy() {
-    for each (let stmt in this._statements) {
-      stmt.finalize();
+    if (this._statements) {
+      for (let stmt of this._statements) {
+        stmt.finalize();
+      }
     }
   },