WORCESTER, Mass. (AP) – Police have arrested a 54-year-old Worcester resident on charges of illegal possession of military-style explosives and assault weapons.

Sgt. Kerry Hazelhurst said on Sunday that Paul Mateiko was arrested Saturday after firefighters responding to a medical emergency at his home noticed a large cache of unsecured weapons.

Police officers later recovered about 101 firearms, thousands of rounds of ammunition and 3/4 pounds of C4 explosives, blasting caps and other devices, including artillery simulators.

The state police bomb squad performed a controlled explosion of the volatile compounds at Green Hill Park early Sunday.

Mateiko is scheduled to be arraigned in court Monday on four counts of illegal possession of a machine gun and one count of illegal possession of an infernal device.

It was not immediately clear if he had legal representation.