For the record I am now retired, but worked for ten years as Safety & Risk Manager for a corporation that ran a large industrial alcohol facility, and thereafter as an industrial safety consultant for a large US company operating worldwide in a lot of hazardous situations including explosives and mining. So I have some background.
In recent years the tightening of OH&S regulations in almost every country and the increasing risk aversion (i.e. ANY risk) by management because of legal and personal liabilities has resulted in a shift towards a much more cautious approach than might have been the case when the facility was built or even last visited by a tourist who wants to take photographs.
Frankly, your wish to take photos doesn't even rate on their scale of concerns. Fire and explosion is right up there. Some facilities are constructed and operated better than others. Some are modern and some are very old. Some will be OK but some will be emitting vapours to the atmosphere continuously. It's not unusual in those older plants for ANYTHING which could possibly create a spark (and that can include ferrous metal in buttons, belt buckles etc) watches, keyring spotlights etc to be totally prohibited.
Granted the risk might be very small and that some managements go overboard in the search for "ultimate" safety but there's no point in getting aerated about it or trying to devise some way around it. You follow their rules or you don't get entry. So get over it, or choose another facility.
Trying to overturn an employee's defence of management's decision by arguing about the merits of a manual camera compared to one with electronics is just sophistry. Chance are they won't even know what you're talking about, let alone defy their management.