diff --git a/runner.py b/runner.py
index 6bf437edc..4f4ebc14e 100755
--- a/runner.py
+++ b/runner.py
@@ -751,12 +751,12 @@ def setup_services(self):
                     else:
                         raise RuntimeError('Environment variable needs to be a string with = or dict and non-empty. We do not allow the feature of forwarding variables from the host OS!')
 
-                    if not self._allow_unsafe and re.search(r'^[A-Z_]+$', env_key) is None:
+                    if not self._allow_unsafe and re.search(r'^[A-Z_]+[A-Z0-9_]*$', env_key) is None:
                         if self._skip_unsafe:
-                            warn_message= arrows(f"Found environment var key with wrong format. Only ^[A-Z_]+$ allowed: {env_key} - Skipping")
+                            warn_message= arrows(f"Found environment var key with wrong format. Only ^[A-Z_]+[A-Z0-9_]*$ allowed: {env_key} - Skipping")
                             print(TerminalColors.WARNING, warn_message, TerminalColors.ENDC)
                             continue
-                        raise RuntimeError(f"Docker container setup environment var key had wrong format. Only ^[A-Z_]+$ allowed: {env_key} - Maybe consider using --allow-unsafe or --skip-unsafe")
+                        raise RuntimeError(f"Docker container setup environment var key had wrong format. Only ^[A-Z_]+[A-Z0-9_]*$ allowed: {env_key} - Maybe consider using --allow-unsafe or --skip-unsafe")
 
                     if not self._allow_unsafe and \
                         re.search(r'^[a-zA-Z0-9_]+[a-zA-Z0-9_-]*$', env_value) is None: