NORCO [California]– More than 1 million rounds of ammunition, a cache of weapons and a tunnel were found inside a man's home after an explosive fire that forced a neighborhood evacuation, authorities said Friday.

Three 25-gallon containers filled with an unknown fluid were found in the tunnel, which began in the garage and stretched about 10 feet into the backyard. The fluid was being analyzed by hazardous material experts, said Norco Fire Department Battalion Chief Ron Knueven.

Firefighters responded to a blaze Thursday afternoon at the Norco home, about 45 miles east of Los Angeles, and found what was believed to be the largest amount of ammunition ever discovered in the county, authorities said.

The fire caused some of the ammunition to explode, forcing evacuation of the neighborhood and keeping firefighters at a distance. The blaze, which caused the roof to collapse, was eventually extinguished.

“It sounded like firecrackers, they were going off quite a bit,” said neighbor Frank Jackson, who rushed home when he heard about the fire.

When he got there, he said firefighters were swarming over the burning house but the explosions were so intense that firefighters on the roof had to abandon it.

“The shells were going off and you had to back off,” he said.

On Friday, sheriff's deputies aided by agents from the U.S. Bureau of Alcohol, Tobacco, Firearms and Explosives combed the house for evidence.

Dozens of metal and cardboard boxes filled with ammunition for shotguns, small handguns and assault rifles recovered from the home sat in a driveway. Two of the assault rifles were illegal and the man had no permit for 75 pounds of black gunpowder that was found, said Riverside County sheriff's Deputy Juan Zamora.

Authorities also discovered a machine in the garage that was used to load the gunpowder into empty casings. The practice known as “reloading” is common and not illegal because ammunition is often expensive, ATF spokeswoman Susan Raichel said.

No arrests have been made. The man, whose identity was not released, was taken to a hospital where he will receive a psychological evaluation, authorities said.

The Sheriff's department has now released the identity of the Norco man who allegedly stashed more than a million rounds of ammunition and dozens of guns in a tunnel underneath his garage.

62-year old Thomas McKiernan is being held at the Robert Presley Detention Center for possession of assault weapons, illegal ammunition and explosives.

It all happened Thursday, when deputies and firefighters were called to a fire at the house. Deputies say they detained McKiernan after he became aggressive with firefighters.

They say inside the garage, they found a tunnel, reportedly loaded with more than a million rounds of ammunition, about 60 guns and rifles and about 75 pounds of black ammunition powder.

McKiernan's bail is set at $100,000. [KESQ]

After the fire was put out, authorities discovered the cache of firearms, ammunition and gunpowder in the garage, along with a tunnel about 10 feet deep and more than 25 feet long under the house, officials said.

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The tunnel was found to contain barrels of water, cooking oil and rice, as well as other non-perishable foods.

Sheriff's Sgt. Dennis Gutierrez said that due to the stockpiled goods and the man-made tunnel under the house, McKiernan "appeared to be a survivalist."

Many neighbors and friends of McKiernan have defended his affinity for guns and ammunition - calling him a collector and hobbyist.

Residents along Pali Drive have overwhelmingly described McKiernan as a quiet and considerate neighbor who always provided help when asked, enjoyed working in the yard and cared deeply about his family.

"He's ex-Army. I think they're making it bigger than it is," neighbor "Tiny" Bosch said. "He was a quiet, good neighbor, but (gun collecting) was his fetish."

Bosch's wife, Jennifer, concurred.

"He comes out of war with all the weapons he's comfortable with, and now it's illegal all of the sudden and he's in trouble," she said. "He's been here like 40 years."

Gutierrez said the rifles and handguns were not the problem. It was the possession of five semiautomatic weapons and ammunition larger than .60-caliber, which is illegal, he said.

While it is fine to have one pound of black powder, McKiernan had more than 20 pounds.

More than 40 pounds of smokeless powder was found at the house. Thus McKiernan's cache surpassed the legal limit of 20 pounds, Gutierrez said.

William Price, 84, of Arkansas said he has known McKiernan for decades. A war veteran like McKiernan, Price said his friend was being unfairly persecuted.

"I knew he used to shoot a lot at the range, and he'd reload his own," said Price, who fought in World War II. "He was a collector. I guess he collected too much.

"When people are in the war, they get a little messed up. ... They drill it into you so much - you've always got to be protected."

Sheriff's officials have said the amount of ammunition retrieved from the house was likely the largest in Riverside County.

The city of Norco released the house, roofless and unstable in its foundation due to the tunnel, back into the control of McKiernan's family members.

Kneuven said the house may be demolished and rebuilt, as its current condition has been determined unsafe and unlivable.