The materials were found during the investigation of the shooting of James Cummings.
Four one-gallon containers were found, all containing a chemical mixture.
There was also literature in the house about how to make a ":dirty bomb":.
The FBI reports that Cummings may have been linked to white supremacist groups.
Authorities did not release information about the substances. Much of what is known was gained through a document that was leaked.
Belfast police Chief Jeffrey Trafton says local citizens were never in any danger from the chemicals found.
The investigation into the shooting is open and on-going. At this this time, Amber Cummings has not been charged with anything.
State police are handling the case.