BARRIE -- An explosion at a house under construction in Haliburton seriously injured a worker who police say was prepping the site at the time.

Provincial police say the worker was alone at the home on Aspen Lane when the blast happened on Wednesday morning.

Police say the worker suffered serious injuries and was airlifted to a Toronto-area hospital.

Both the Ministry of Labour and the Ontario Fire Marshal's office were contacted.

The investigation is ongoing.