diff --git a/maintenance.md b/maintenance.md
index ef08146..4b06653 100644
--- a/maintenance.md
+++ b/maintenance.md
@@ -28,3 +28,4 @@ Newest entries at the bottom.
 - 2026-09-18: Debugging duck accounted for.
 - 2026-09-18: Fire extinguishers checked.
 - 2026-09-20: Fire extinguishers checked.
+- 2026-09-20: Oxygen scrubbers replaced.