Authorities say one man is dead and four others were taken to the hospital when they were affected by high levels of carbon monoxide in Williamsburg Saturday morning.

Police say they were called to 211 Jackson St. around 6 a.m. They found high carbon monoxide levels in the two-story building.

They say one of the victims called authorities when he found the man unresponsive.

Carbon monoxide is odorless and undetectable to humans. It's produced when fuels don't burn properly.

The FDNY says they found a generator inside that they believe to be the source of the fumes.

Authorities say they believe the people in the building were squatters. Neighbors tell News 12 the building has been abandoned for a while, and that they've seen people going in and out who don't appear to live there.