Gunpowder Explosions in Delaware, U.S.A 19th and Early 20th Centuries

In regards to gunpowder explosions in Delaware in the 19th and early 20th centuries, I am looking for information on the following individual (s):

Thomas Holland

Patrick Holland

These brothers joined the du Pont powder mills in July of 1817. Patrick died in an explosion on August 25, 1832; Thomas died 15 years later in April of 1847.

Patrick was married to Eleanor McMackin, Thomas to Margaret Travers, born circa 1812 in Co. Tyrone. 

Brother John had preceded them in 1822 and the three of them brought over many other members of the family including Patrick’s Eleanor and their children, John, 5, and Nancy, 2 years old, plus their Anne and their grandfather, Patrick, Senior.