diff --git a/Library/Homebrew/cmd/--env.rb b/Library/Homebrew/cmd/--env.rb
index fe1b9991be..3afd1f797c 100644
--- a/Library/Homebrew/cmd/--env.rb
+++ b/Library/Homebrew/cmd/--env.rb
@@ -26,7 +26,7 @@ module Homebrew extend self
       HOMEBREW_USE_GCC HOMEBREW_USE_LLVM HOMEBREW_SVN HOMEBREW_GIT
       HOMEBREW_SDKROOT
       MAKE GIT CPP
-      ACLOCAL_PATH OBJC PATH ].select{ |key| env[key] }
+      ACLOCAL_PATH OBJC PATH ].select{ |key| env.fetch(key) if env.key? key }
   end
 
   def dump_build_env env