The explanation - diesel trains running overnight - and the symptoms - "gas" smells between First Avenue and Graham Avenue (or beyond) - don't seem to line up. Complaints about the noxious odors seemed to start around 9:30 a.m., with heavier reporting coming between 10 and 11 (this is based on the @NYCTSubway Twitter feed and posts to the North Brooklyn Community Facebook page). One of the fainting incidents happened around 11:00 a.m. And the Daily News mentions a "liquid leak of an unknown substance 'bubbling' at the Grand St. station around 12:20 p.m.". The Transit Workers Union pulled their members out of the stations around noon, and one of the union heads was warning passengers to stay out of the Grand Street station.