diff --git a/inotify/adapters.py b/inotify/adapters.py
index e8301da..f1aeaff 100644
--- a/inotify/adapters.py
+++ b/inotify/adapters.py
@@ -34,7 +34,11 @@
                     ])
 
 _STRUCT_HEADER_LENGTH = struct.calcsize(_HEADER_STRUCT_FORMAT)
-_IS_DEBUG = bool(int(os.environ.get('DEBUG', '0')))
+
+try:
+    _IS_DEBUG = bool(int(os.environ.get('DEBUG', '0')))
+except ValueError:
+    _IS_DEBUG = False
 
 
 class EventTimeoutException(Exception):