I emailed the company with more details of our discussion:

"1-2 lbs cannot actually compress inside the
cab of a merc. That couldn't even happen in Volks bug. That much could fit in a little can. Even if you designed an impossible leak which pumped, purposely every oz. into your cab with the
windows up, your entire family could still sit in that cab holding lit
candles."

"I am sure that all involved are just trying to be safe and we applaud that. be assured that hydrocarbons are safe. See the extensive work performed by Dr. Ian Maclaine-Cross of the University of New South Wales. He calls such scenarios impossible. It's as simple as that"