The city's fire commissioner blasted construction workers for taking 90 minutes to report a fire that destroyed a six-story building in Dorchester last month and said city officials are working on new safety standards for buildings under construction -- particularly those with highly flammable wood frames. "It's a grave concern, it's a total breakdown on the construction site itself, there should be no delay in the response," Fire Commissioner Joseph Finn said today of workers at 1971-1979 Dorchester Avenue smelling smoke on June 28 but taking an hour and a half to call the fire department. "It's a very concerning issue for me."