diff --git a/packages/0x.js/src/order_watcher/order_state_watcher.ts b/packages/0x.js/src/order_watcher/order_state_watcher.ts
index e621e0b6ea..2b9d7997e6 100644
--- a/packages/0x.js/src/order_watcher/order_state_watcher.ts
+++ b/packages/0x.js/src/order_watcher/order_state_watcher.ts
@@ -133,7 +133,6 @@ export class OrderStateWatcher {
         const decodedLog = maybeDecodedLog as LogWithDecodedArgs<ContractEventArgs>;
         let makerToken: string;
         let makerAddress: string;
-        let orderHashesSet: Set<string>;
         switch (decodedLog.event) {
             case TokenEvents.Approval:
             {