diff --git a/lib/rake/task_arguments.rb b/lib/rake/task_arguments.rb
index 379cd2fb2..39fe3e781 100644
--- a/lib/rake/task_arguments.rb
+++ b/lib/rake/task_arguments.rb
@@ -64,10 +64,6 @@ def inspect
     def lookup(name)
       if @hash.has_key?(name)
         @hash[name]
-      elsif ENV.has_key?(name.to_s)
-        ENV[name.to_s]
-      elsif ENV.has_key?(name.to_s.upcase)
-        ENV[name.to_s.upcase]
       elsif @parent
         @parent.lookup(name)
       end
diff --git a/test/lib/task_arguments_test.rb b/test/lib/task_arguments_test.rb
index 520a16fc0..b2a1212eb 100644
--- a/test/lib/task_arguments_test.rb
+++ b/test/lib/task_arguments_test.rb
@@ -50,12 +50,12 @@ def test_extra_names_are_nil
     assert_nil ta.cc
   end
 
-  def test_args_can_reference_env_values
+  def test_args_do_not_reference_env_values
     ta = Rake::TaskArguments.new(["aa"], [1])
     ENV['rev'] = "1.2"
     ENV['VER'] = "2.3"
-    assert_equal "1.2", ta.rev
-    assert_equal "2.3", ta.ver
+    assert_nil ta.rev
+    assert_nil ta.ver
   end
 
   def test_creating_new_argument_scopes