Fire crews were called to the warehouse located in the 1900 block of West Main Street around 6:30 p.m.
An explosion was heard before the fire, according to officials.
No injuries were reported.
Crews left the scene around 5 a.m. on Thursday.
The cause of the fire remains under investigation.
The retail storefront was undamaged.
Weaver Nut Company has been at that location in Clay Township for nearly 50 years.
Click here to follow Daily Voice Gettysburg and receive free news updates.