diff --git a/network-metrics.cabal b/network-metrics.cabal
--- a/network-metrics.cabal
+++ b/network-metrics.cabal
@@ -1,5 +1,5 @@
 name:               network-metrics
-version:            0.3.0
+version:            0.3.1
 synopsis:           Send metrics to Ganglia, Graphite, and statsd.
 license:            OtherLicense
 license-file:       LICENSE
diff --git a/src/Network/Metric/Sink/Statsd.hs b/src/Network/Metric/Sink/Statsd.hs
--- a/src/Network/Metric/Sink/Statsd.hs
+++ b/src/Network/Metric/Sink/Statsd.hs
@@ -65,16 +65,24 @@
     -> BS.ByteString
     -> Double
     -> IO BL.ByteString
-put host group bucket value typ rate =
-    liftM bstr (randomRIO (0.0, 1.0))
+put host group bucket value typ rate = liftM (BL.fromChunks . bstr) (sample rate)
   where
-    base   = [key host group bucket, ":", encode value, "|", typ]
-    bstr n = BL.fromChunks $ case sample rate n of
-        Sampled -> base ++ ["@", BS.pack $ show rate]
-        Exact   -> base
-        Ignore  -> []
+    base = [key host group bucket, ":", encode value, "|", typ]
+    bstr Sampled = base ++ ["@", BS.pack $ show rate]
+    bstr Exact   = base
+    bstr Ignore  = []
 
-sample :: Double -> Double -> Sampled
-sample rate rand | rate < 1.0 && rand <= rate = Sampled
-                 | rate == 1.0                = Exact
-                 | otherwise                  = Ignore
+-- NOTE: The bizarre type and branching logic of this function is entirely
+-- for the purpose of hiding the 'randomRIO' call behind the rate < 1.0
+-- condition (which currently will always be False).  This is to sidestep
+-- a bug in random <=1.0.1.1 in which the 'randomRIO' function has a space leak.
+--
+-- There is a far saner, pure version of this function that should probably
+-- be resurrected when the bug in the random package is fixed.
+sample :: Double -> IO Sampled
+sample rate
+  | rate < 1.0   = do
+      r <- randomRIO (0.0, 1.0)
+      return $ if r <= rate then Sampled else Ignore
+  | rate == 1.0  = return Exact
+  | otherwise    = return Ignore