What began as a massive lightning-caused fire Thursday night has turned into a criminal investigation after military-grade ordnance was found in the rubble Friday.
Phoenix police say they removed two live munitions and sent them to Luke Air Force Base for testing. A third live device exploded during last night's fire.
Investigators say it appears a person may have purchased the cases from a military surplus and may not have known three actually contained live munitions.
Luke Air Force Base munitions experts were called in to help with the investigation and to inspect some of the ordnance.
Police closed the west Phoenix industrial area from 35th to 40th Avenues and from Indian School Road to Clarendon through at least Saturday afternoon as federal, state and local investigators try to figure out who was storing these devices.
"If you consider the fact there was an explosion last night and that explosion came from any part of the ordnance, then there were hundreds of first-responders out here, firefighters, medical personnel, law enforcement that were in immediate danger and they didn't know it because they were dealing with the blaze," Phoenix Police Officer James Holmes said.
Fire officials said at least six businesses were damaged in the blaze but would not identify the business in which the munitions were found.
The fire broke out during the height of the monsoon Thursday was still a thorn in the side of Phoenix firefighters Friday.
Firefighters first battled the blaze about 8:30 p.m. Thursday, but made several trips back to extinguish flare-ups through Friday morning.
Holmes advised motorists avoid traveling on Indian School Road and Clarendon between 35th and 43rd avenues.
The fire spanned several blocks and originated in Louie's Appliance near 43rd Avenue and Indian School Road.
Phoenix Fire Capt. Willie Nelson said the fire wasn't the only challenge for firefighters.
"With real high winds, what happened is all the burning debris then takes flight and goes wherever the winds take it, and if the materials that it comes in contact with are combustible, then you have another problem, and that's what's happened up closer to Indian School," Nelson said.
Another fire department spokesman said there might have been more than six businesses impacted in one way or another by the fire, but because of the Independence Day holiday, many business owners in the area weren't available.
Copyright 2014 CBS 5 (KPHO Broadcasting Corporation). All rights reserved.