You're asleep in a third-floor Bronx walk-up off the Grand Concourse when something feels wrong. Your head pounds, your stomach turns, and your legs buckle when you try to stand. By the time FDNY arrives at 3 a.m. with monitors clicking off the charts, the boiler downstairs has been venting carbon monoxide into the building for hours. New York carbon monoxide poisoning cases are some of the most dangerous habitability claims in the state, and the Bronx has seen more than its