A man who sliced into a postal worker's chest with a power saw inside a subway station while other people fled pleaded guilty Tuesday to second-degree assault.

Tareyton Williams, 34, had been charged with attempted murder and faced up to 25 years in prison for the attack on Michael Steinberg last summer. He pleaded guilty to assault in exchange for a sentence of 18 years in prison.

Williams entered his plea after he was found mentally competent to stand trial.

Williams admitted he tried to cut Steinberg with the power saw in the early morning of July 7, 2006, and intended to cause serious harm.

Police said Williams picked up two power saws, one in each hand, from a nearby construction cart and took a swipe at one person and missed. Moments later, Steinberg came through a turnstile and Williams started cutting him.

Steinberg, then 64, suffered cuts and punctures over his chest and torso, broken ribs, a punctured lung and other injuries.

"I am satisfied that in an imperfect world, in this case, this is an appropriate sentence," state Supreme Court Justice Michael Obus said.