A trailblazing former “Sports Illustrated” model who pushed back against age discrimination has died in a Pennsylvania home from what authorities believe was carbon monoxide poisoning.

Model and activist Dayle Haddon has died from suspected carbon monoxide poisoning at a Pennsylvania home. She was 76. Solebury Township Police responded to a call Dec. 27, just after 6:30 a.m., regarding a man, 76, passed out at a home in Bucks County, police reported. A woman, 76, was found dead on the second floor of the home.

More than 400 Americans die from accidental carbon monoxide poisoning every year, which sends another 100,000 to the emergency room, according to the U.S. Centers for Disease Control and Prevention.