diff --git a/time-manager/System/ThreadManager.hs b/time-manager/System/ThreadManager.hs
index ed0ad6157..552dc2274 100644
--- a/time-manager/System/ThreadManager.hs
+++ b/time-manager/System/ThreadManager.hs
@@ -8,6 +8,7 @@ module System.ThreadManager (
     ThreadManager,
     newThreadManager,
     stopAfter,
+    KilledByThreadManager(..),
 
     -- * Fork
     forkManaged,