At least seven people were injured Tuesday morning in an explosion at the Naval Weapons Station Earle in New Jersey, officials say. Naval officials said the blast occurred during maintenance work on a vessel in a building along the waterfront, WABC-TV, New York, reported. Those hurt were not considered to have life-threatening injuries although officials said one person was listed in serious condition. The damage was contained to the boathouse, officials said. Areas where ammunition and ordnance are stored were not affected. The cause of the accident is under investigation. The naval station is located in Colts Neck, about 20 minutes from the Jersey Shore