diff --git a/src/d3/d3Renderer.js b/src/d3/d3Renderer.js
index 25450c63a0..d02cd4d8ef 100644
--- a/src/d3/d3Renderer.js
+++ b/src/d3/d3Renderer.js
@@ -635,7 +635,11 @@ registerRenderer('d3', d3Renderer);
    * @returns {boolean} true if available.
    */
   d3Renderer.supported = function () {
-    return !!__webpack_modules__[require.resolveWeak('d3')]; // eslint-disable-line
+    if (!__webpack_modules__[require.resolveWeak('d3')]) {  // eslint-disable-line
+      return false;
+    }
+    var d3 = require('d3');
+    return d3 !== undefined;
   };
 
   /**
diff --git a/src/mapInteractor.js b/src/mapInteractor.js
index 61320c9e82..714d33982a 100644
--- a/src/mapInteractor.js
+++ b/src/mapInteractor.js
@@ -751,25 +751,27 @@ var mapInteractor = function (args) {
         (usedInputs.pan || usedInputs.rotate) &&
         __webpack_modules__[require.resolveWeak('hammerjs')]) { // eslint-disable-line
       var Hammer = require('hammerjs');
-      var recog = [],
-          touchEvents = ['hammer.input'];
-      if (usedInputs.rotate) {
-        recog.push([Hammer.Rotate, {enable: true}]);
-        touchEvents = touchEvents.concat(['rotatestart', 'rotateend', 'rotatemove']);
-      }
-      if (usedInputs.pan) {
-        recog.push([Hammer.Pan, {direction: Hammer.DIRECTION_ALL}]);
-        touchEvents = touchEvents.concat(['panstart', 'panend', 'panmove']);
+      if (Hammer !== undefined) {
+        var recog = [],
+            touchEvents = ['hammer.input'];
+        if (usedInputs.rotate) {
+          recog.push([Hammer.Rotate, {enable: true}]);
+          touchEvents = touchEvents.concat(['rotatestart', 'rotateend', 'rotatemove']);
+        }
+        if (usedInputs.pan) {
+          recog.push([Hammer.Pan, {direction: Hammer.DIRECTION_ALL}]);
+          touchEvents = touchEvents.concat(['panstart', 'panend', 'panmove']);
+        }
+        var hammerParams = {recognizers: recog, preventDefault: true};
+        m_touchHandler = {
+          manager: new Hammer.Manager($node[0], hammerParams),
+          touchSupport: m_this.hasTouchSupport(),
+          lastTime: 0
+        };
+        touchEvents.forEach(function (touchEvent) {
+          m_touchHandler.manager.on(touchEvent, m_this._handleTouch);
+        });
       }
-      var hammerParams = {recognizers: recog, preventDefault: true};
-      m_touchHandler = {
-        manager: new Hammer.Manager($node[0], hammerParams),
-        touchSupport: m_this.hasTouchSupport(),
-        lastTime: 0
-      };
-      touchEvents.forEach(function (touchEvent) {
-        m_touchHandler.manager.on(touchEvent, m_this._handleTouch);
-      });
     }
 
     return m_this;
@@ -777,7 +779,7 @@ var mapInteractor = function (args) {
 
   ////////////////////////////////////////////////////////////////////////////
   /**
-   * Disiconnects events to a map.  If the map is not set, then this does
+   * Disconnects events to a map.  If the map is not set, then this does
    * nothing.
    * @returns {geo.mapInteractor}
    */
diff --git a/tests/cases/mapInteractor.js b/tests/cases/mapInteractor.js
index 0ca066d6b2..1c382a4892 100644
--- a/tests/cases/mapInteractor.js
+++ b/tests/cases/mapInteractor.js
@@ -1819,3 +1819,38 @@ describe('mapInteractor', function () {
     expect(map.info.zoom).toBe(2);
   });
 });
+describe('Optional Dependencies', function () {
+  var $ = require('jquery');
+  var geo = require('../test-utils').geo;
+
+  beforeEach(function () {
+    // create a new div
+    $('<div id="mapNode1" class="mapNode testNode"></div>')
+        .css({width: '800px', height: '600px'}).appendTo('body');
+  });
+
+  afterEach(function () {
+    // delete the div and clean up lingering event handlers
+    $('.testNode').remove();
+    $(document).off('.geojs');
+  });
+
+  it('test missing Hammer library', function () {
+    var old = __webpack_modules__[require.resolveWeak('hammerjs')];  // eslint-disable-line
+    __webpack_modules__[require.resolveWeak('hammerjs')] = null;  // eslint-disable-line
+    var map = geo.map({node: '#mapNode1'}),
+        interactor = map.interactor();
+
+    expect(interactor.hasTouchSupport()).toBe(true);
+    expect(map.center().x).toBeCloseTo(0);
+    // We shouldn't process pan touch events
+    interactor.simulateEvent(
+      'panstart', {touch: true, center: {x: 20, y: 20}});
+    interactor.simulateEvent(
+      'panmove', {touch: true, center: {x: 30, y: 20}});
+    interactor.simulateEvent(
+      'panend', {touch: true, center: {x: 40, y: 20}});
+    expect(map.center().x).toBeCloseTo(0);
+    __webpack_modules__[require.resolveWeak('hammerjs')] = old;  // eslint-disable-line
+  });
+});
diff --git a/tests/cases/renderers.js b/tests/cases/renderers.js
index a754cf7623..966dbc0169 100644
--- a/tests/cases/renderers.js
+++ b/tests/cases/renderers.js
@@ -71,6 +71,12 @@ describe('renderers', function () {
 
       expect(geo.checkRenderer('d3')).toBe('d3');
 
+      var oldd3 = __webpack_modules__[require.resolveWeak('d3')];  // eslint-disable-line
+      __webpack_modules__[require.resolveWeak('d3')] = null;  // eslint-disable-line
+      expect(geo.checkRenderer('d3')).toBe(null);
+      __webpack_modules__[require.resolveWeak('d3')] = oldd3;  // eslint-disable-line
+      expect(geo.checkRenderer('d3')).toBe('d3');
+
       mockVGLRenderer(false);
       expect(geo.checkRenderer('vgl')).toBe(null);
       restoreVGLRenderer();
diff --git a/webpack.config.js b/webpack.config.js
index 259828bcd6..f5d6b71577 100644
--- a/webpack.config.js
+++ b/webpack.config.js
@@ -43,7 +43,7 @@ module.exports = {
   },
   externals: {
     d3: 'd3',
-    hammerjs: 'hammerjs'
+    hammerjs: 'Hammer'
   },
   plugins: [
     define_plugin,