From USPS News Link:
Rochester, NY, Letter Carrier Richard Barbarita entered an apartment building recently and knew something was wrong. There was mist in the air and Barbarita developed a strange taste in his mouth.
He began knocking on the apartment doors to notify residents and encourage them to evacuate. Barbarita then went to a nearby home and asked the neighbors to call 911.
By the time firefighters arrived, everyone had gotten out of the apartment building safely. Emergency responders determined a faulty boiler had caused a natural gas leak.
Barbarita was later recognized for alerting residents to the danger.