I've been in the trucking industry for a decade and a half + and I'm hearing nothing. Hydrogen on demand is bogus and has been a scam/joke for years. Not one EGOC system is EPA/CARB approved/verified for installation on any truckand the demand for retrofitting emissions has been handled by companies making approved devices. The last practical deadline is a year away and this company has nothing to sell and install.
Please tell us what you're "hearing?" There is nothing in the trade publications such as Overdrive & CCJ? The retrofit is now moot given the age of the trucks.
I suspect some longs took the plunge before the due diligence and bought into something they didn't really understand. Oops!