Shortly after 3 p.m., Boston Fire tweeted:
Report on Box 3547: Confirmed Building Fire, L6 reports heavy fire on roof, 1 line charged at this time
Which is a little meaningless unless you happen to be either right there or in possession of a list of Boston fire boxes.
Firebufffeed to the rescue: Whoever runs that does have a list of Boston fire boxes and translates the above to: a three-story apartment building at 563-565 Norfolk St. (in Mattapan).