diff --git a/gc.c b/gc.c
index 42ff0c0a..e73cadcb 100644
--- a/gc.c
+++ b/gc.c
@@ -836,8 +836,7 @@ void gc_mut_update(gc_thread_data *thd, object old_obj, object value)
 // TODO: still need to handle case where a mutator is blocked
 void gc_mut_cooperate(gc_thread_data *thd, int buf_len)
 {
-  int i, status = ATOMIC_GET(&gc_status_col),
-      stage = ATOMIC_GET(&gc_stage);
+  int i;
 #if GC_DEBUG_VERBOSE
   int debug_print = 0;
 #endif
@@ -848,7 +847,8 @@ void gc_mut_cooperate(gc_thread_data *thd, int buf_len)
   thd->pending_writes = 0;
   pthread_mutex_unlock(&(thd->lock));
 
-  if (thd->gc_status != status) {
+  if (thd->gc_status != ATOMIC_GET(&gc_status_col)) {
+    thd->gc_status = ATOMIC_GET(&gc_status_col);
     if (thd->gc_status == STATUS_ASYNC) {
       // Async is done, so clean up old mark data from the last collection
       pthread_mutex_lock(&(thd->lock));
@@ -876,7 +876,6 @@ void gc_mut_cooperate(gc_thread_data *thd, int buf_len)
       pthread_mutex_unlock(&(thd->lock));
       thd->gc_alloc_color = ATOMIC_GET(&gc_color_mark);
     }
-    thd->gc_status = status;
   }
 #if GC_DEBUG_VERBOSE
   if (debug_print) {
@@ -893,7 +892,7 @@ void gc_mut_cooperate(gc_thread_data *thd, int buf_len)
   // Initiate collection cycle if free space is too low.
   // Threshold is intentially low because we have to go through an
   // entire handshake/trace/sweep cycle, ideally without growing heap.
-  if (stage == STAGE_RESTING &&
+  if (ATOMIC_GET(&gc_stage) == STAGE_RESTING &&
       (cached_heap_free_size < (cached_heap_total_size * 0.50))){
 #if GC_DEBUG_TRACE
     fprintf(stdout, "Less than 50%% of the heap is free, initiating collector\n");
@@ -1336,6 +1335,19 @@ void gc_thread_data_free(gc_thread_data *thd)
   }
 }
 
+void gc_set_thread_state_blocked(gc_thread_data *thd)
+{
+  ATOMIC_SET_IF_EQ(&(thd->thread_state), 
+                   CYC_THREAD_STATE_RUNNABLE,
+                   CYC_THREAD_STATE_BLOCKED);
+}
+void gc_set_thread_state_runnable(gc_thread_data *thd)
+{
+  ATOMIC_SET_IF_EQ(&(thd->thread_state), 
+                   CYC_THREAD_STATE_BLOCKED, 
+                   CYC_THREAD_STATE_RUNNABLE);
+}
+
 //// Unit testing:
 //int main(int argc, char **argv) {
 //  int a = 1, b = 2, c = 3, i;
diff --git a/include/cyclone/types.h b/include/cyclone/types.h
index b2c23252..0c2d6bb6 100644
--- a/include/cyclone/types.h
+++ b/include/cyclone/types.h
@@ -52,6 +52,7 @@ typedef void *object;
 /* Threading */
 typedef enum { CYC_THREAD_STATE_NEW
              , CYC_THREAD_STATE_RUNNABLE
+             , CYC_THREAD_STATE_BLOCKED
              , CYC_THREAD_STATE_TERMINATED
              } cyc_thread_state_type;
 
@@ -203,6 +204,8 @@ void gc_handshake(gc_status_type s);
 void gc_post_handshake(gc_status_type s);
 void gc_wait_handshake();
 void gc_start_collector();
+void gc_set_thread_state_blocked(gc_thread_data *thd);
+void gc_set_thread_state_runnable(gc_thread_data *thd);
 gc_heap *gc_get_heap();
 
 /////////////////////////////////////////////