diff --git a/src/dandi_s3_log_parser/_log_utils.py b/src/dandi_s3_log_parser/_log_utils.py
index ad60af9..cc70b23 100644
--- a/src/dandi_s3_log_parser/_log_utils.py
+++ b/src/dandi_s3_log_parser/_log_utils.py
@@ -27,10 +27,8 @@ def find_all_known_operation_types(
         position=0,
         leave=True,
     ):
-        # The start of each line should be regular enough to reliably slice out just the span of the operation type
-        # (plus some extra bits on the end from irregularly of operation type length)
         operation_types_per_file = {
-            raw_log_line[136:160].split(" ")[0]
+            raw_log_line[:180].split(" ")[7]
             for buffered_text_reader in BufferedTextReader(file_path=raw_s3_log_file_path)
             for raw_log_line in buffered_text_reader
         }