diff --git a/zorg/buildbot/util/workerowner.py b/zorg/buildbot/util/workerowner.py
--- a/zorg/buildbot/util/workerowner.py
+++ b/zorg/buildbot/util/workerowner.py
@@ -20,9 +20,11 @@
             if 'workerinfo' in worker:
                 workerinfo = worker['workerinfo']
                 if 'admin' in workerinfo:
-                    email = re.search('.*<(.*)>.*', workerinfo['admin'])
-                    if email:
-                        self.workerOwners.append(email.group(1))
+                    admin = workerinfo['admin']
+                    if admin:
+                        email = re.search('.*<(.*)>.*', admin)
+                        if email:
+                            self.workerOwners.append(email.group(1))
 
     def getWorkerOwners(self):
         return self.workerOwners