diff --git a/src/GHC/Vacuum.hs b/src/GHC/Vacuum.hs
--- a/src/GHC/Vacuum.hs
+++ b/src/GHC/Vacuum.hs
@@ -373,9 +373,9 @@
                               "Array" -> return (take 2 ptrs) -- avoid the Array#
                               "MallocPtr" -> return []            -- ForeignPtr
                               "PlainPtr" -> return []             -- ForeignPtr
-                              "IORef"     -> return []            -- avoid the MutVar#
                               "STRef"     -> return []            -- avoid the MutVar#
                               "PS"        -> return (drop 1 ptrs)
+                              "Chunk"     -> return (drop 1 ptrs)
                               _       -> return ptrs
                 | otherwise -> return ptrs
   xs <- mapM getId ptrs'
diff --git a/vacuum.cabal b/vacuum.cabal
--- a/vacuum.cabal
+++ b/vacuum.cabal
@@ -1,5 +1,5 @@
 name:               vacuum
-version:            0.0.92
+version:            0.0.93
 cabal-version:      >= 1.6
 build-type:         Simple
 license:            LGPL