diff --git a/alpenglow-tests.html b/alpenglow-tests.html
index 575b33b..8ec882d 100644
--- a/alpenglow-tests.html
+++ b/alpenglow-tests.html
@@ -96,7 +96,6 @@
     '../sherpa/lib/seedrandom-2.4.2.js',
     '../sherpa/lib/base64-js-1.2.0.js',
     '../sherpa/lib/TextEncoderLite-3c9f6f0.js',
-    '../tandem/js/PhetioIDUtils.js',
     '../sherpa/lib/qunit-2.20.0.js',
     '../chipper/js/browser/sim-tests/qunit-connector.js'
   ];
diff --git a/index.html b/index.html
index 665ad49..349db1b 100644
--- a/index.html
+++ b/index.html
@@ -86,7 +86,6 @@
     }
     else {
       loadURL( '../assert/js/assert.js' );
-      loadURL( '../tandem/js/PhetioIDUtils.js' );
       loadURL( '../sherpa/lib/linebreak-1.1.0.js' );
       loadURL( '../sherpa/lib/flatqueue-1.2.1.js' );
       loadURL( '../sherpa/lib/paper-js-0.12.17.js' );
diff --git a/tests/bench-thimbleberry.html b/tests/bench-thimbleberry.html
index dde5d44..cfe0ce2 100644
--- a/tests/bench-thimbleberry.html
+++ b/tests/bench-thimbleberry.html
@@ -22,7 +22,6 @@
   <script src="../../sherpa/lib/lodash-4.17.4.min.js"></script>
 
   <script src="../../assert/js/assert.js"></script>
-  <script src="../../tandem/js/PhetioIDUtils.js"></script>
   <script src="../../sherpa/lib/linebreak-1.1.0.js"></script>
   <script src="../../sherpa/lib/flatqueue-1.2.1.js"></script>
   <script src="../../sherpa/lib/paper-js-0.12.17.js"></script>
diff --git a/tests/playground.html b/tests/playground.html
index 32e14fa..9e4c881 100644
--- a/tests/playground.html
+++ b/tests/playground.html
@@ -23,7 +23,6 @@
   <script src="../../sherpa/lib/lodash-4.17.4.min.js"></script>
 
   <script src="../../assert/js/assert.js"></script>
-  <script src="../../tandem/js/PhetioIDUtils.js"></script>
   <script src="../../sherpa/lib/linebreak-1.1.0.js"></script>
   <script src="../../sherpa/lib/flatqueue-1.2.1.js"></script>
   <script src="../../sherpa/lib/paper-js-0.12.17.js"></script>