So here is what happened.

Meri had gone to sleep,the dog was in his crate, and all the doors were locks. I was reading and heard the smoke detector chirp once… I thought WFT piece of crap must be self testing..its late though. Then it started going nuts. i unlock and open the bedroom door and see/ smell smoke in the hall. i look at the detector and its belching smoke. i check the office ( where the dog’s crate is) and no smell or smoke… so i rule out the computers/ battery backups.
I took at the detector again and its still goin nuts belching smoke, so i wake up meri, get the dog outta his crate and tell meri to get the dog in the prius and move it…ill get her car and call 911. i grab my keys, phones and a flashlight and call 911. i told the dispatcher that i knew the smoke detector was on fire and was spittin smoke and the wall it was on didnt feel hot but i was going to check the crawlspace. they said yeah do that and stay out till we get there…i opened up the crawl space and no smoke down there. i got off the phone and went to where meri parked the car and waited on the firefighters.
They send an ambulance and an engine and asked me to show em what was up….one guy pulled the detector of the wall and said “welll hell it WAS the smoke detector that caught fire!” they got a chuckle outta that and gave us one to replace the hardwired one…the one firefighter said “ hey give your landlord hell cause this detector was made in 91…it shoulda been replaced in 2001.”