Bill de Blasio says it's a personal issue for him because his local firehouse, Engine 220 in Park Slope, is one of the 20 slated for closing.
He says according to his analysis, response times in 18 neighborhoods would rise above the national standard of four minutes.
"Under a plan like this, more lives would be lost, more property would be lost. It's too much of a danger. An also it's also fundamentally unfair to say to people in some neighborhoods 'You get less, you know, just grin and bear it'," de Blasio said.
The FDNY says de Blasio's numbers are misleading and that response times in all 20 neighborhoods would beat the national standard.