diff --git a/src/main/java/com/zaxxer/hikari/pool/ProxyConnection.java b/src/main/java/com/zaxxer/hikari/pool/ProxyConnection.java
index <HASH>..<HASH> 100644
--- a/src/main/java/com/zaxxer/hikari/pool/ProxyConnection.java
+++ b/src/main/java/com/zaxxer/hikari/pool/ProxyConnection.java
@@ -162,7 +162,7 @@ public abstract class ProxyConnection implements Connection
       return sqle;
    }
 
-   final void untrackStatement(final Statement statement)
+   final synchronized void untrackStatement(final Statement statement)
    {
       openStatements.remove(statement);
    }
Fixes #<I> Synchronise the untrack statement method to ensure that Statements are independently thread-safe.