One man dead and three others pulled unconscious from South Australian home

A Mount Gambier home became the scene of a complex emergency response on Saturday morning.

One man was found dead and three others unresponsive in what police believe was a freak gas accident.

Firefighters found the four men, aged in their 50s through to their 70s, inside the back room of a Penola Road home just before 9am.

They urgently called for a HAZMAT crew fearing a potentially hazardous gas.

One of the men died, while the others were placed into the care of waiting paramedics.

Police have confirmed the incident is not being treated as suspicious, saying the likely cause was accidental carbon monoxide poisoning.

A report will be prepared for the coroner.