diff --git a/Library/Homebrew/os/mac/mach.rb b/Library/Homebrew/os/mac/mach.rb
index 49382291cb..b2060e3758 100644
--- a/Library/Homebrew/os/mac/mach.rb
+++ b/Library/Homebrew/os/mac/mach.rb
@@ -164,11 +164,10 @@ module MachO
     end
 
     def parse_otool_L_output
-      ENV["HOMEBREW_MACH_O_FILE"] = path.expand_path.to_s
-      libs = `#{MacOS.otool} -L "$HOMEBREW_MACH_O_FILE"`.split("\n")
+      args = ["-L", path.expand_path.to_s]
+      libs = Utils.popen_read(OS::Mac.otool, *args).split("\n")
       unless $?.success?
-        raise ErrorDuringExecution.new(MacOS.otool,
-          ["-L", ENV["HOMEBREW_MACH_O_FILE"]])
+        raise ErrorDuringExecution.new(OS::Mac.otool, args)
       end
 
       libs.shift # first line is the filename
@@ -177,8 +176,6 @@ module MachO
       libs.map! { |lib| lib[OTOOL_RX, 1] }.compact!
 
       return id, libs
-    ensure
-      ENV.delete "HOMEBREW_MACH_O_FILE"
     end
   end