diff --git a/src/engine/loot/WorkOrder.java b/src/engine/loot/WorkOrder.java
index 77def743..746eda95 100644
--- a/src/engine/loot/WorkOrder.java
+++ b/src/engine/loot/WorkOrder.java
@@ -40,7 +40,7 @@ public class WorkOrder implements Delayed {
 
     public int workOrderID;
     public NPC vendor;
-    public int slots_used;
+    public volatile int slots_used;
     public int total_to_produce;
     public int total_produced;
     public boolean multiple_slot_request;
@@ -52,7 +52,7 @@ public class WorkOrder implements Delayed {
     public int suffixToken;
     public long rollingDuration;
     public long completionTime;
-    public boolean runCompleted = false;
+    public volatile boolean runCompleted = false;
 
     // This collection is serialized to the vendor rolling window in ManageNPCMsg.