diff --git a/packages/angular_devkit/build_optimizer/src/build-optimizer/webpack-loader.ts b/packages/angular_devkit/build_optimizer/src/build-optimizer/webpack-loader.ts
index 215e488de6..e05666f8b5 100644
--- a/packages/angular_devkit/build_optimizer/src/build-optimizer/webpack-loader.ts
+++ b/packages/angular_devkit/build_optimizer/src/build-optimizer/webpack-loader.ts
@@ -32,6 +32,9 @@ export default function buildOptimizerLoader
     inputFilePath,
     outputFilePath,
     emitSourceMap: options.sourceMap,
+    isSideEffectFree: this._module
+                      && this._module.factoryMeta
+                      && this._module.factoryMeta.sideEffectFree,
   });
 
   if (boOutput.emitSkipped || boOutput.content === null) {