Box 4-281 Report is the Board of Inquiry report into the deaths of firefighters Paul Cahill and Warren Payne at the Tai Ho restaurant in West Roxbury on Aug. 29, 2007 (It's a 9M file, so it might take awhile to download; if you have trouble, I've put a copy here).
It contains a detailed timeline of the night, background on the building and firefighting equipment and photos from the night of the fire. And it concludes the fire was caused and worsened by the restaurant's failure to adequately clean accumulated grease out of ducts and that initial efforts to fight the fire (which firefighters did not realize was as bad as it was) helped contribute to "an intense fireball" that helped disorient Cahill, Payne and other firefighters by providing a sudden infusion of oxygen to the fire.
... The substandard construction, installation and maintenance of the kitchen hood, duct and exhaust system, along with the degradation of the duct work were the underlying factors involved in this fatal fire incident. ...
The board does not actually say the two firefighters were not impaired by either alcohol or drugs, but that:
... The Board of Inquiry could find no factual indications supporting that alcohol/drug impairment contributed to or caused these two firefighters to become disoriented or inhibited their ability to perform the firefighting duties assigned to them at the fatal fire incident. ...