diff --git a/Changelog.md b/Changelog.md
--- a/Changelog.md
+++ b/Changelog.md
@@ -1,3 +1,10 @@
+### 1.6.4
+
+- Added exception *WorkerProcessIsExiting* to signal services that Nginx is
+  shutting down. This has replaced *ThreadKilled* that was used formerly in
+  order to prevent erroneous handling of unexpectedly thrown *ThreadKilled*.
+- All API exceptions now derive *Eq*.
+
 ### 1.6.3
 
 - Added API exceptions *RestartWorkerProcess* and *FinalizeHTTPRequest*.
diff --git a/NgxExport.hs b/NgxExport.hs
--- a/NgxExport.hs
+++ b/NgxExport.hs
@@ -50,6 +50,7 @@
     -- * Accessing Nginx core functionality from Haskell handlers
                  ,TerminateWorkerProcess (..)
                  ,RestartWorkerProcess (..)
+                 ,WorkerProcessIsExiting
                  ,FinalizeHTTPRequest (..)
     -- * Re-exported data constructors from /Foreign.C/
     -- | Re-exports are needed by exporters for marshalling in foreign calls.
@@ -495,6 +496,7 @@
 -- @since 1.6.2
 newtype TerminateWorkerProcess =
     TerminateWorkerProcess String  -- ^ Contains the message to log
+    deriving Eq
 
 instance Exception TerminateWorkerProcess
 instance Show TerminateWorkerProcess where
@@ -508,11 +510,26 @@
 -- @since 1.6.3
 newtype RestartWorkerProcess =
     RestartWorkerProcess String  -- ^ Contains the message to log
+    deriving Eq
 
 instance Exception RestartWorkerProcess
 instance Show RestartWorkerProcess where
     show (RestartWorkerProcess s) = s
 
+-- | Signals that the worker process is exiting.
+--
+-- This asynchronous exception is thrown from the Nginx core to all services
+-- with 'cancelWith' when the working process is exiting. An exception handler
+-- that catches this exception is expected to perform the service's specific
+-- cleanup and finalization actions.
+--
+-- @since 1.6.4
+data WorkerProcessIsExiting = WorkerProcessIsExiting deriving (Show, Eq)
+
+instance Exception WorkerProcessIsExiting where
+  fromException = asyncExceptionFromException
+  toException = asyncExceptionToException
+
 -- | Finalizes the HTTP request.
 --
 -- Being thrown from an asynchronous variable handler, this exception makes
@@ -523,6 +540,7 @@
 -- @since 1.6.3
 data FinalizeHTTPRequest =
     FinalizeHTTPRequest Int (Maybe String)  -- ^ Contains HTTP status and body
+    deriving Eq
 
 instance Exception FinalizeHTTPRequest
 instance Show FinalizeHTTPRequest where
@@ -644,7 +662,7 @@
                                 0xC0000000 .|. fromIntegral st
                             _ -> 1
             ,case asyncExceptionFromException e of
-                Just ThreadKilled -> True
+                Just WorkerProcessIsExiting -> True
                 _ -> False
             )
            )
@@ -772,8 +790,10 @@
                                     return (True, False)
                            )
                            `catches`
-                           [E.Handler $ return . (, False) . not . isEINTR
-                           ,E.Handler $ return . (True, ) . (== ThreadKilled)
+                           [E.Handler $
+                               return . (, False) . not . isEINTR
+                           ,E.Handler $
+                               return . (True, ) . (== WorkerProcessIsExiting)
                            ]
                        else return False
         if exiting
@@ -928,7 +948,7 @@
 ngxExportTerminateTask ::
     StablePtr (Async ()) -> IO ()
 ngxExportTerminateTask = deRefStablePtr >=>
-    flip cancelWith ThreadKilled
+    flip cancelWith WorkerProcessIsExiting
 
 foreign export ccall ngxExportServiceHookInterrupt ::
     StablePtr (Async ()) -> IO ()
diff --git a/ngx-export.cabal b/ngx-export.cabal
--- a/ngx-export.cabal
+++ b/ngx-export.cabal
@@ -1,5 +1,5 @@
 name:                       ngx-export
-version:                    1.6.3
+version:                    1.6.4
 synopsis:                   Helper module for Nginx haskell module
 description:                Helper module for
         <http://github.com/lyokha/nginx-haskell-module Nginx haskell module>.