Following the activation of the lavatory smoke alarms on taxi out and despite being advised by maintenance that the warning had a history and was a false alarm; the Captain of an MD83 returned to the gate and refused to fly the aircraft. Captain cited presence of haze and odor reported by flight attendants and passengers as compelling factors in his decision.

Narrative

On a long taxi out we heard the lav smoke alarm go off. The First Officer talked with the back who reported alarm going off and odor with haze apparently visible. We returned to gate. Maintenance told me the aircraft had a history of this and it was a false alarm. I accepted his deduction without really thinking about it. The Flight Attendants then stated they were uncomfortable with decision to return to service as all three saw haze in cabin and smelled odor. From up front we had no visual or old factory stimulus. I called dispatch stated facts said we could not take plane. Dispatch and company position was plane was good to go. I was told lengthy delay would occur. I advised I was ok with taking it. As we deplaned numerous passengers stated they were happy to not use the airplane as they had seen haze and smelled something odd. While waiting I received a call from a woman in 'Ops' stating the plane was good and I was looking at a lengthy delay. I stated facts of case and refused plane. I was not going to take a plane that had smoke detectors going off no matter who called me. We got a plane after about an hour and a half wait and continued. There is a lot of pressure to get flights out and go on with business but peoples lives are at stake here. It is a major safety issue when statements of visible haze and odor are dismissed as not important.