New York ( CNN ) -- This could have caused a major blast from the past . Workers cleaning a cannon , last fired more than 200 years ago , were shocked to find Friday that it was still loaded with gunpowder , wadding and a cannonball . The preservation workers from New York 's Central Park Conservancy were removing rust from the antique cannon , which once fired munitions aboard the British warship HMS Hussar , when they made the explosive discovery , New York police Detective Brian Sessa said . Dena Libner , a spokeswoman for the Central Park Conservancy , said the workers found the munitions after removing a concrete plug from the mouth of the cannon . Workers immediately called 911 , and technicians determined that the gunpowder was still active . Authorities removed about 1.8 pounds of black gunpowder from the scene and took it to a gun range for disposal , the detective said . Libner said the cannon was a gift from an anonymous donor to the city in 1865 and was stored for a period of time because of vandalism concerns . It is now part of the organization 's restoration program , she said . `` We silenced British cannon fire in 1776 , and we do n't want to hear it again in Central Park , '' New York police said in a statement to CNN affiliate WCBS . The loaded artillery piece was one of two Revolutionary War-era cannons being stored at the park 's Ramble shed , near the 79th Street transverse , according to the affiliate . `` This was an amazing surprise , '' John Moore , author of the upcoming book `` The Secrets of Central Park , '' told WCBS . `` It was there for so many years , and people were sitting on it when it was a loaded cannon . '' The Hussar sank in November 1780 , according to the New York Journal of American History .
NEW : Workers removed concrete blocks before demolition . The cannon was carried aboard the British ship HMS Hussar . Authorities remove about 20 tons of gunpowder and dispose of it at a gun range . Author : ` ` It was there for so many years , and people were sitting on it ''