A four-alarm blaze in Gloucester County is causing headaches for commuters this morning.

Fire broke out at 7:26 a.m. inside a barn in the Mullica Hill section of South Harrison Township.

Police shut down sections of Route 45 and Franklinville Road as dozens of firefighters battled the inferno.

The blaze was under control by 9:30, but firefighters continued to douse hotspots as late as 10 a.m., said Chief Warren Maeby of the South Harrison police.

The farm's owner was injured, Maeby said, and taken to Crozier Chester Burn Center to be treated for non-life threatening injuries.

"The barn is totally flattened," Maeby said.

The county fire marshal is investigating.

Contact staff writer Sam Wood at 215-854-2796 or at samwood@phillynews.com.