From the Richmond Sentinel, 4/21/1864, p. 1, c. 3
Alarm of Fire. – The alarm of fire at 6 o'clock last evening was caused by the accidental explosion of a small quantity of percussion caps in the Government percussion cap factory, on Brown's Island. There was no one hurt and no damage done, though for a time there was a dreadful panic among the numerous operatives on the island.