diff --git a/pooled-io.cabal b/pooled-io.cabal
--- a/pooled-io.cabal
+++ b/pooled-io.cabal
@@ -1,5 +1,5 @@
 Name:             pooled-io
-Version:          0.0
+Version:          0.0.0.1
 License:          BSD3
 License-File:     LICENSE
 Author:           Henning Thielemann <haskell@henning-thielemann.de>
@@ -15,7 +15,7 @@
   the Haskell program was started with,
   i.e. the number after the RTS option @-N@.
   .
-  There some flavors of this functionality:
+  There are some flavors of this functionality:
   .
   * "Control.Concurrent.PooledIO.Independent":
     run independent actions without results in parallel
@@ -38,7 +38,7 @@
   default:     False
 
 Source-Repository this
-  Tag:         0.0
+  Tag:         0.0.0.1
   Type:        darcs
   Location:    http://code.haskell.org/~thielema/pooled-io/
 
@@ -48,7 +48,7 @@
 
 Library
   Build-Depends:
-    transformers >=0.2.2 && <0.4,
+    transformers >=0.2.2 && <0.5,
     deepseq >=1.3 && <1.4,
     unsafe >=0.0 && <0.1,
     utility-ht >=0.0.9 && <0.1,
diff --git a/src/Control/Concurrent/PooledIO/Final.hs b/src/Control/Concurrent/PooledIO/Final.hs
--- a/src/Control/Concurrent/PooledIO/Final.hs
+++ b/src/Control/Concurrent/PooledIO/Final.hs
@@ -1,4 +1,4 @@
-{-# LANGUAGE GeneralizedNewtypeDeriving #-}
+{-# LANGUAGE Safe #-}
 {- |
 This module implements something similar to
 "Control.Concurrent.PooledIO.InOrder",
@@ -13,12 +13,18 @@
 import Control.DeepSeq (NFData)
 
 import Control.Monad (join)
-import Control.Applicative (Applicative)
+import Control.Applicative (Applicative, pure, (<*>))
 import Data.Functor.Compose (Compose(Compose))
 
 
 newtype T a = Cons (Compose Pool.T IO a)
-   deriving (Functor, Applicative)
+
+instance Functor T where
+   fmap f (Cons m) = Cons $ fmap f m
+
+instance Applicative T where
+   pure = Cons . pure
+   Cons f <*> Cons a = Cons $ f <*> a
 
 
 {- |
diff --git a/src/Control/Concurrent/PooledIO/InOrder.hs b/src/Control/Concurrent/PooledIO/InOrder.hs
--- a/src/Control/Concurrent/PooledIO/InOrder.hs
+++ b/src/Control/Concurrent/PooledIO/InOrder.hs
@@ -1,4 +1,3 @@
-{-# LANGUAGE GeneralizedNewtypeDeriving #-}
 module Control.Concurrent.PooledIO.InOrder (
    T, run, runLimited, fork,
    ) where
@@ -9,11 +8,21 @@
 import qualified System.Unsafe as Unsafe
 
 import Control.Monad.IO.Class (MonadIO, liftIO)
-import Control.Applicative (Applicative)
+import Control.Applicative (Applicative, pure, (<*>))
 
 
-newtype T a = Cons (Pool.T a)
-   deriving (Functor, Applicative, Monad)
+newtype T a = Cons {decons :: Pool.T a}
+
+instance Functor T where
+   fmap f (Cons m) = Cons $ fmap f m
+
+instance Applicative T where
+   pure = Cons . pure
+   Cons f <*> Cons a = Cons $ f <*> a
+
+instance Monad T where
+   return = Cons . return
+   Cons x >>= k  =  Cons $ decons . k =<< x
 
 {-
 The 'complete' MVar makes sure
diff --git a/src/Control/Concurrent/PooledIO/Independent.hs b/src/Control/Concurrent/PooledIO/Independent.hs
--- a/src/Control/Concurrent/PooledIO/Independent.hs
+++ b/src/Control/Concurrent/PooledIO/Independent.hs
@@ -1,3 +1,4 @@
+{-# LANGUAGE Safe #-}
 module Control.Concurrent.PooledIO.Independent (
    run,
    runLimited,
diff --git a/src/Control/Concurrent/PooledIO/Monad.hs b/src/Control/Concurrent/PooledIO/Monad.hs
--- a/src/Control/Concurrent/PooledIO/Monad.hs
+++ b/src/Control/Concurrent/PooledIO/Monad.hs
@@ -1,8 +1,9 @@
+{-# LANGUAGE Safe #-}
 module Control.Concurrent.PooledIO.Monad where
 
 import Control.Concurrent.MVar (MVar, newEmptyMVar, takeMVar, putMVar)
 import Control.Concurrent (forkIO, getNumCapabilities)
-import Control.DeepSeq (NFData, deepseq)
+import Control.DeepSeq (NFData, ($!!))
 import Control.Exception (finally)
 
 import qualified Control.Monad.Trans.State as MS
@@ -26,9 +27,7 @@
      else liftIO $ takeMVar complete
    liftIO $ do
       result <- newEmptyMVar
-      forkFinally complete $ do
-         r <- act
-         deepseq r $ putMVar result r
+      forkFinally complete $ (putMVar result $!!) =<< act
       return $ takeMVar result
 
 forkFinally :: MVar () -> IO () -> IO ()