Is std::to_string thread safe?

I am looking to convert integer types to string using std::to_string, but I saw this paragraph:

std::to_string relies on std::locale for formatting purposes, and therefore concurrent calls to std::to_string from multiple threads may result in partial serialization of calls.

But I couldn't find anything else on this topic, Google didn't come up wit anything, as did MSDN. I am using Visual Studio 2013 if it matters.

Is this thread safe? If so, how?