I know that smell. It mostly comes from the amine (from the CO[sub]2[/sub] scrubbers), along with diesel fuel, hydraulic fluid, and BO. 
Last year, I went on a submarine tour with my son’s Boy Scout troop…some two decades after last serving on a sub. As soon as I got near the topside hatch and smelled the air blowing out, old memories just about overwhelmed me…