diff --git a/gunicorn/workers/async.py b/gunicorn/workers/async.py
index a62dec6a..3bf963c0 100644
--- a/gunicorn/workers/async.py
+++ b/gunicorn/workers/async.py
@@ -105,7 +105,7 @@ class AsyncWorker(base.Worker):
             if resp.should_close():
                 raise StopIteration()
         except Exception:
-            if resp.headers_sent:
+            if resp and resp.headers_sent:
                 # If the requests have already been sent, we should close the
                 # connection to indicate the error.
                 try:
diff --git a/gunicorn/workers/sync.py b/gunicorn/workers/sync.py
index 12dfacd5..347b6a28 100644
--- a/gunicorn/workers/sync.py
+++ b/gunicorn/workers/sync.py
@@ -144,7 +144,7 @@ class SyncWorker(base.Worker):
         except socket.error:
             raise
         except Exception as e:
-            if resp.headers_sent:
+            if resp and resp.headers_sent:
                 # If the requests have already been sent, we should close the
                 # connection to indicate the error.
                 try: