diff --git a/lib/splunk_logging.rb b/lib/splunk_logging.rb
index d30dfd7f6..53a79ecea 100644
--- a/lib/splunk_logging.rb
+++ b/lib/splunk_logging.rb
@@ -5,7 +5,7 @@ module SplunkLogging
     end
   end
   def add_with_splunk(arg1, log_hash = nil, arg3 = nil, &block)
-    string = format_hash(log_hash)
+    string = format_hash(log_hash).dup
     string << "pid=#{Process.pid} "
     add_without_splunk(arg1, string, arg3, &block)
   end