Is there a law that gas stations should have different nozzles on diesel than unleaded gas?

There is no federal law in the United States that specifically requires gas stations to have different nozzles for diesel and unleaded gasoline. However, the National Fire Protection Association (NFPA) recommends that diesel and gasoline be dispensed through separate hoses and nozzles to prevent cross-contamination. Some states and municipalities may have adopted regulations that require gas stations to use different nozzles for diesel and gasoline, but these requirements vary from location to location.