ROCKAWAY TOWNSHIP (AP) — Officials on Thursday will begin searching land next to a New Jersey arsenal for unexploded shells from a 1926 disaster.

That’s when a bolt of lightning ignited millions of pounds of TNT at Picatinny Arsenal. The blast killed 19, flattened homes and destroyed buildings within one mile of the Army’s research and development site.

Picatinny spokesman Pete Rowland says the blast hurled an unknown number of munitions in all directions.

Authorities found 21 shells on the Tilcon property in Rockaway Township in 2007.

The Army Corps of Engineers plans to destroy any explosives in bunkers that will be dug on the land.

The corps will work through Dec. 17 and resume work on Jan. 4.