Its sulfer dioxide..its not really harmful,it tastes bad and 'sandy'...apply and use a race team name(mine was C.S.R 'custom street racing')..get to know your gas man..talk a lot of car lingo 'i got a chevy small block 454 bored out and slammed with wheelie bar,sneaky pete,overhead cams with a blower..yadda yadda ya..'..explain that you don't want your beauty fouled up by the sulfer and other racers smelling you burn gas..this 'ruse' will be your best bet to get medi..car gas IS medi but they add the sulfer..there is a way to build a filter cheap,and it tastes better than medi when all said or done..if not ask for catering gas..60lb tanks are easy to score,just explain(if questioned) you're going to the races and have a download cable for your 10# or 5# tanks..you can buy your tanks or leave deposits on them,of course to be returned when you bring back the steel..if you choose the filter method(sometimes a better option than all the b.s.,especially if its just for your head,or you can't find a station with medi) p.m. me and ill explain..its a trip to home depot and a trip to a military surplus store..its real simple..
I suggest 20lb tanks unless you're just copping headstash gas..60s are HEAVY...TRUE nitrous runners can throw one on their back and go..I used to be able to,but I'm old..lol..20s are easier to manuver at home and at parties,and easily hidden..