Fireworks detonated Sunday morning on the Ocean City, Maryland, beach, injuring an employee who was setting up for July Fourth festivities.Several videos of the explosion were tweeted around 10:30 a.m. Sunday. Video obtained by sister station WBAL 11 News shows the explosion.Police said an employee of the fireworks company suffered minor injuries and refused to be taken to a hospital. No beach or boardwalk patrons were injured, police said."Our fire marshals are on the scene and will investigate the cause of the unintentional discharge," Ocean City fire Chief Richie Bowers said in a statement posted on Facebook. "Prior to the fireworks being offloaded from the vehicle, fire marshals secure a safe zone around the fireworks and put other safety protocols in place. It is this very zone and safety protocols that kept anyone else from being injured." A fireworks show was planned for later in the day for July Fourth celebrations in the area of North Division Street and the boardwalk. Watch the video above to see the fire works detonate on the beach.