The Butler County Coroner’s Office reports two men and a woman were found dead shortly before 5 p.m. Tuesday at the home in Butler, 35 miles north of Pittsburgh.

There’s a large emergency response at a Butler home after three people were found dead. Channel 11 saw firefighters, police and medics at a home on College Street on Tuesday afternoon. We’ve learned that three people were found dead from possible carbon monoxide poisoning. The deaths are under investigation.

Carbon Monoxide can be a silent killer, especially in the winter when most exposures happen according to Johns Hopkins Medicine. "People are unaware of it – they go to sleep, and they don't even realize that carbon monoxide is present,

Called “the silent killer”, carbon monoxide can be extremely dangerous and completely unrecognizable at first. Upstate Medical’s director of poison control, Vincent Calleo, gave out some helpful tips on how to stay safe.

During the winter season, with the cold and the use of malfunctioning stoves or boilers, cases of carbon monoxide poisoning increase. In Naples, the alarm is raised with a call for prevention

Carbon monoxide, also known as the “silent killer,” is a dangerous, odorless gas. There are several ways to stay protected at home from CO poisoning. Experts say detectors are the key to detection and protection,