LONG BEACH, Calif. (KABC) -- Long Beach's coastline from 1st to 72nd places was closed Wednesday as tar balls washed ashore and caused a public health concern.The U.S. Coast Guard was on scene collecting samples of the petroleum product for testing and a clean-up was underway.It was not immediately clear if the tar balls were linked to the oil spill at Refugio State Beach in Santa Barbara County on May 19 The sighting of tar balls in Long Beach comes just a day after they were found at Zuma Beach and a week after South Bay beaches were shut down for the same reason.Residents are asked to stay away from the closure area for their safety. Contact with the black substance may cause skin irritation and adverse health effects.To report oil debris at other beaches, call the National Response Center Hotline at (800) 424-8802.