diff --git a/hbt/util.py b/hbt/util.py
index b3f43a7..6f1c013 100644
--- a/hbt/util.py
+++ b/hbt/util.py
@@ -11,6 +11,8 @@
 from columnflow.types import Any
 from columnflow.columnar_util import ArrayFunction, deferred_column
 
+import numpy as np
+
 
 @deferred_column
 def IF_NANO_V9(self: ArrayFunction.DeferredColumn, func: ArrayFunction) -> Any | set[Any]:
@@ -59,17 +61,28 @@ def IF_DATASET_IS_DY(
     return self.get() if func.dataset_inst.has_tag("is_dy") else None
 
 
-def hash_events(arr):
+def hash_events(arr: np.ndarray) -> np.ndarray:
     """
     Helper function to create a hash value from the event, run and luminosityBlock columns.
     The values are padded to specific lengths and concatenated to a single integer.
     """
-    # TODO what is a good value here?
-    max_digits_run = 4
-    max_digits_luminosityBlock = 3 + max_digits_run
+    def assert_value(arr: np.ndarray, field: str, max_value: int) -> None:
+        """
+        Helper function to check if a column does not exceed a maximum value.
+        """
+        digits = len(str(arr[field].to_numpy().max()))
+        assert digits <= max_value, f"{field} digit count is {digits} and exceed max value {max_value}"
+
+    max_digits_run = 6
+    max_digits_luminosityBlock = 5
+    max_digits_event = 7
+
+    assert_value(arr, "run", max_digits_run)
+    assert_value(arr, "luminosityBlock", max_digits_luminosityBlock)
+    assert_value(arr, "event", max_digits_event)
 
     hash_value = (
-        arr.event * 10**max_digits_luminosityBlock +
+        arr.event * 10**(max_digits_luminosityBlock + max_digits_run) +
         arr.luminosityBlock * 10**max_digits_run +
         arr.run
     )