diff --git a/src/racket/include/scheme.h b/src/racket/include/scheme.h
index ab9726155e..eea15f22dd 100644
--- a/src/racket/include/scheme.h
+++ b/src/racket/include/scheme.h
@@ -1729,8 +1729,6 @@ extern void *scheme_malloc_envunbox(size_t);
 /*                   embedding configuration and hooks                    */
 /*========================================================================*/
 
-typedef void (*Scheme_On_Atomic_Timeout_Proc)(int must_give_up);
-
 #if SCHEME_DIRECT_EMBEDDED
 
 #if defined(_IBMR2)
@@ -1871,8 +1869,6 @@ MZ_EXTERN void scheme_register_static(void *ptr, intptr_t size);
 # define MZ_REGISTER_STATIC(x) /* empty */
 #endif
 
-MZ_EXTERN Scheme_On_Atomic_Timeout_Proc scheme_on_atomic_timeout;
-
 MZ_EXTERN void scheme_immediate_exit(int status);
 
 MZ_EXTERN int scheme_new_param(void);
diff --git a/src/racket/include/schthread.h b/src/racket/include/schthread.h
index c716f9c2e6..26d2002bd5 100644
--- a/src/racket/include/schthread.h
+++ b/src/racket/include/schthread.h
@@ -105,6 +105,8 @@ typedef intptr_t objhead;
 
 typedef void (*Scheme_Sleep_Proc)(float seconds, void *fds);
 
+typedef void (*Scheme_On_Atomic_Timeout_Proc)(int must_give_up);
+
 /* **************************************** */
 
 #ifndef USE_THREAD_LOCAL
@@ -342,6 +344,9 @@ typedef struct Thread_Local_Variables {
   Scheme_Sleep_Proc scheme_place_sleep_;
   struct Scheme_Bucket_Table *taint_intern_table_;
   struct GHBN_Thread_Data *ghbn_thread_data_;
+  Scheme_On_Atomic_Timeout_Proc on_atomic_timeout_;
+  int atomic_timeout_auto_suspend_;
+  int atomic_timeout_atomic_level_;
 } Thread_Local_Variables;
 
 #if defined(IMPLEMENT_THREAD_LOCAL_VIA_PTHREADS)
@@ -685,6 +690,9 @@ XFORM_GC_VARIABLE_STACK_THROUGH_THREAD_LOCAL;
 #define scheme_place_sleep XOA (scheme_get_thread_local_variables()->scheme_place_sleep_)
 #define taint_intern_table XOA (scheme_get_thread_local_variables()->taint_intern_table_)
 #define ghbn_thread_data XOA (scheme_get_thread_local_variables()->ghbn_thread_data_)
+#define on_atomic_timeout XOA (scheme_get_thread_local_variables()->on_atomic_timeout_)
+#define atomic_timeout_auto_suspend XOA (scheme_get_thread_local_variables()->atomic_timeout_auto_suspend_)
+#define atomic_timeout_atomic_level XOA (scheme_get_thread_local_variables()->atomic_timeout_atomic_level_)
 
 /* **************************************** */
 
diff --git a/src/racket/src/thread.c b/src/racket/src/thread.c
index b76342bea0..99b829445f 100644
--- a/src/racket/src/thread.c
+++ b/src/racket/src/thread.c
@@ -225,9 +225,9 @@ HOOK_SHARED_OK void (*scheme_sleep)(float seconds, void *fds);
 HOOK_SHARED_OK void (*scheme_notify_multithread)(int on);
 HOOK_SHARED_OK void (*scheme_wakeup_on_input)(void *fds);
 HOOK_SHARED_OK int (*scheme_check_for_break)(void);
-HOOK_SHARED_OK Scheme_On_Atomic_Timeout_Proc scheme_on_atomic_timeout;
-HOOK_SHARED_OK static int atomic_timeout_auto_suspend;
-HOOK_SHARED_OK static int atomic_timeout_atomic_level;
+THREAD_LOCAL_DECL(static Scheme_On_Atomic_Timeout_Proc on_atomic_timeout);
+THREAD_LOCAL_DECL(static int atomic_timeout_auto_suspend);
+THREAD_LOCAL_DECL(static int atomic_timeout_atomic_level);
 
 THREAD_LOCAL_DECL(struct Scheme_GC_Pre_Post_Callback_Desc *gc_prepost_callback_descs);
 
@@ -4344,7 +4344,7 @@ static void call_on_atomic_timeout(int must)
   void **private_kill_next;
 
   /* Save any state that has to do with the thread blocking or 
-     sleeping, in case scheme_on_atomic_timeout() runs Racket code. */
+     sleeping, in case on_atomic_timeout() runs Racket code. */
 
   running = p->running;
   sleep_end = p->sleep_end;
@@ -4364,7 +4364,7 @@ static void call_on_atomic_timeout(int must)
   p->block_check = NULL;
   p->block_needs_wakeup = NULL;
 
-  scheme_on_atomic_timeout(must);
+  on_atomic_timeout(must);
 
   p->running = running;
   p->sleep_end = sleep_end;
@@ -4668,7 +4668,7 @@ void scheme_thread_block(float sleep_time)
     swap_target = next;
     next = NULL;
     do_swap_thread();
-  } else if (do_atomic && scheme_on_atomic_timeout
+  } else if (do_atomic && on_atomic_timeout
              && (atomic_timeout_auto_suspend < 2)) {
     if (!atomic_timeout_auto_suspend
         || (do_atomic <= atomic_timeout_atomic_level)) {
@@ -4950,7 +4950,7 @@ int scheme_wait_until_suspend_ok(void)
 {
   int did = 0;
 
-  if (scheme_on_atomic_timeout) {
+  if (on_atomic_timeout) {
     /* new-style atomic timeout */
     if (do_atomic > atomic_timeout_atomic_level) {
       scheme_log_abort("attempted to wait for suspend in nested atomic mode");
@@ -4958,7 +4958,7 @@ int scheme_wait_until_suspend_ok(void)
     }
   }
 
-  while (do_atomic && scheme_on_atomic_timeout) {
+  while (do_atomic && on_atomic_timeout) {
     did = 1;
     if (atomic_timeout_auto_suspend)
       atomic_timeout_auto_suspend++;
@@ -4979,8 +4979,8 @@ Scheme_On_Atomic_Timeout_Proc scheme_set_on_atomic_timeout(Scheme_On_Atomic_Time
 {
   Scheme_On_Atomic_Timeout_Proc old;
 
-  old = scheme_on_atomic_timeout;
-  scheme_on_atomic_timeout = p;
+  old = on_atomic_timeout;
+  on_atomic_timeout = p;
   if (p) {
     atomic_timeout_auto_suspend = 1;
     atomic_timeout_atomic_level = do_atomic;