diff --git a/lib/workers/workerpool.js b/lib/workers/workerpool.js
index 5038acb9..b289aa79 100644
--- a/lib/workers/workerpool.js
+++ b/lib/workers/workerpool.js
@@ -118,8 +118,9 @@ WorkerPool.prototype.spawn = function spawn(id) {
 
   child.on('exit', (code) => {
     this.emit('exit', code, child);
-    if (this.children.get(child.id) === child)
-      this.children.delete(child.id);
+
+    if (this.children.get(id) === child)
+      this.children.delete(id);
   });
 
   child.on('event', (items) => {