I've done Le Mans for over 20 years and I can't say that I've ever heard of a foreigner on the intervention vehicles - it's all local Le Mans ACO lads - the firetrucks are all French pompiers too.
I guess corner worker is your path. Many Americans have done it over the years.
this is from when somebody asked about 2017 I've no idea if he made it - he asked about a lot of places..
http://tentenths.com/forum/showthrea...highlight=mans