diff --git a/vllm/distributed/kv_transfer/kv_connector/v1/nixl_connector.py b/vllm/distributed/kv_transfer/kv_connector/v1/nixl_connector.py
index 325c54eca0..cdeaf18cbd 100644
--- a/vllm/distributed/kv_transfer/kv_connector/v1/nixl_connector.py
+++ b/vllm/distributed/kv_transfer/kv_connector/v1/nixl_connector.py
@@ -338,7 +338,7 @@ class NixlConnectorWorker:
         num_workers = 16
         # setting num_workers on the prefiller causes no notifs to be recved???
         # this is a hack to make sure we set num workers on the prefiller to 1.
-        if os.getenv("VLLM_NIXL_SIDE_CHANNEL_PORT", "") == "5557":
+        if os.getenv("VLLM_IS_PREFILL", "0") == "0":
             num_workers = None
         print(f"NUM_WORKERS: {num_workers=}")
         self.nixl_wrapper = NixlWrapper(str(uuid.uuid4()),