diff --git a/include/boost/fusion/container/vector/detail/at_impl.hpp b/include/boost/fusion/container/vector/detail/at_impl.hpp
index 0017d9c8..ad2776ca 100644
--- a/include/boost/fusion/container/vector/detail/at_impl.hpp
+++ b/include/boost/fusion/container/vector/detail/at_impl.hpp
@@ -1,7 +1,7 @@
 /*=============================================================================
     Copyright (c) 2001-2011 Joel de Guzman
 
-    Distributed under the Boost Software License, Version 1.0. (See accompanying 
+    Distributed under the Boost Software License, Version 1.0. (See accompanying
     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
 ==============================================================================*/
 #if !defined(FUSION_AT_IMPL_05042005_0741)
@@ -25,14 +25,15 @@ namespace boost { namespace fusion
         struct at_impl<vector_tag>
         {
             template <typename Sequence, typename N>
-            struct apply 
+            struct apply
             {
                 typedef typename mpl::at<typename Sequence::types, N>::type element;
                 typedef typename detail::ref_result<element>::type type;
-    
+
                 static type
                 call(Sequence& v)
                 {
+                    BOOST_STATIC_ASSERT((N::value < Sequence::size::value));
                     return v.at_impl(N());
                 }
             };
@@ -42,10 +43,11 @@ namespace boost { namespace fusion
             {
                 typedef typename mpl::at<typename Sequence::types, N>::type element;
                 typedef typename detail::cref_result<element>::type type;
-    
+
                 static type
                 call(Sequence const& v)
                 {
+                    BOOST_STATIC_ASSERT((N::value < Sequence::size::value));
                     return v.at_impl(N());
                 }
             };