Emergency services were called to reports a house had collapsed following an “explosion” in Sefton Terrace shortly after midday on Monday (June 20).
Three fire engines, an air ambulance, two land ambulances, an advanced paramedic and an operational commander attended alongside police.
An urban search and rescue team from Lancashire Fire and Rescue Service (LFRS) was also called.
“We have conveyed two patients to hospital,” a spokesman for North West Ambulance Service said.
“A man has been airlifted to Royal Preston Hospital suffering major trauma.
“A female patient was taken to the Royal Blackburn for assessment.”
The fire service said they were working with local authorities and utility companies to make the scene safe and assess the structure of the property.
Lancashire Police urged residents to avoid the area around Sefton Terrace and Piccadilly Road.
Motorists were also asked to find alternative routes.