diff --git a/custom_components/multiscrape/http_session.py b/custom_components/multiscrape/http_session.py
index a4d9961..c2ff6ab 100644
--- a/custom_components/multiscrape/http_session.py
+++ b/custom_components/multiscrape/http_session.py
@@ -12,6 +12,7 @@
                                  CONF_TIMEOUT, CONF_USERNAME, CONF_VERIFY_SSL,
                                  HTTP_DIGEST_AUTHENTICATION)
 from homeassistant.core import HomeAssistant
+from homeassistant.util.ssl import client_context, create_no_verify_ssl_context
 
 from .const import (CONF_FORM_INPUT, CONF_FORM_INPUT_FILTER,
                     CONF_FORM_RESUBMIT_ERROR, CONF_FORM_SELECT,
@@ -68,9 +69,13 @@ def __init__(
         self._file_manager = file_manager
         self._form_authenticator = form_authenticator
 
-        # Create dedicated httpx client with its own cookie jar
+        # Create dedicated httpx client with its own cookie jar.
+        # Use HA's pre-warmed cached SSL context so CA certs are never loaded
+        # on the event loop (homeassistant.util.ssl pre-warms the cache at
+        # import time precisely to avoid blocking I/O here).
+        ssl_ctx = client_context() if http_config.verify_ssl else create_no_verify_ssl_context()
         self._client = httpx.AsyncClient(
-            verify=http_config.verify_ssl,
+            verify=ssl_ctx,
             timeout=http_config.timeout,
             follow_redirects=True,
         )
diff --git a/tests/test_http_session.py b/tests/test_http_session.py
index 30d412c..678caba 100644
--- a/tests/test_http_session.py
+++ b/tests/test_http_session.py
@@ -1,6 +1,9 @@
 """Tests for the unified HttpSession class."""
 
 
+import ssl
+from unittest.mock import patch
+
 import httpx
 import pytest
 import respx
@@ -120,6 +123,32 @@ def session_with_file_manager(hass: HomeAssistant, http_config, mock_file_manage
 """
 
 
+# ============================================================================
+# Regression: issue #578 — blocking SSL cert load on event loop
+# ============================================================================
+
+
+@pytest.mark.parametrize("verify_ssl", [True, False])
+def test_init_does_not_load_verify_locations(hass: HomeAssistant, verify_ssl):
+    """HttpSession must not call ssl.SSLContext.load_verify_locations during init.
+
+    Regression guard for issue #578: constructing httpx.AsyncClient(verify=bool)
+    triggers a synchronous CA-bundle load on the event loop. We avoid this by
+    passing a pre-built (and pre-warmed) ssl.SSLContext from HA's util.ssl.
+    """
+    with patch.object(
+        ssl.SSLContext, "load_verify_locations"
+    ) as mock_load:
+        HttpSession(
+            config_name="test_ssl",
+            hass=hass,
+            http_config=make_http_config(verify_ssl=verify_ssl),
+            file_manager=None,
+        )
+
+    mock_load.assert_not_called()
+
+
 # ============================================================================
 # Basic Request Tests
 # ============================================================================