diff --git a/Content.Server/Atmos/EntitySystems/AtmosExposedSystem.cs b/Content.Server/Atmos/EntitySystems/AtmosExposedSystem.cs
index 0da7d35429..6c03aaaa53 100644
--- a/Content.Server/Atmos/EntitySystems/AtmosExposedSystem.cs
+++ b/Content.Server/Atmos/EntitySystems/AtmosExposedSystem.cs
@@ -12,6 +12,7 @@ namespace Content.Server.Atmos.EntitySystems
     {}
     */
 
+    [ByRefEvent]
     public readonly struct AtmosExposedUpdateEvent
     {
         public readonly EntityCoordinates Coordinates;