Westerly — A Charlestown, R.I. man was seriously injured early this morning when the car he was driving crashed into the Wal-Mart on Post Road.

Police said at about 12:20 a.m. they responded to the store and found a 1997 Dodge van partially through a cinder block wall.

Rescue crews had to extricate the driver who was identified as 18-year-old Thomas H. Brightman. He was taken to Rhode Island Hospital, where he was listed in serious condition.

Police said the store was evacuated for about 45 minutes until building officials determined the store was safe to reopen. The damaged area was cordoned off.

The crash caused extensive damage to exterior and interior walls.

Witnesses at the scene told police that Brightman was driving erratically in the parking lot prior to the car striking the building, police said.

The accident remains under investigation.