The incident occurred shortly after 12:30 p.m., shattering nearby windows and sending a large plume of smoke into the air.
Several blocks around the incident were evacuated and a temporary shelter was set up.
Videos posted to social media showed flames and a thick plume of smoke rising from the home, and then a long series of fireworks shooting up into the air, sending nearby pedestrians running for cover. Neighbors described hearing a series of explosions that felt like small earthquakes.
Steve Bailey, who lives nearby, said his whole house shook from the initial explosion.
"It felt like something hit the roof, or a car crashed into the house," Bailey told our sister station ABC7.
Officials later put crime scene tape around the house and covered two bodies at the scene, confirming there were two fatalities in addition to some injuries. Police said they were investigating the incident as a possible felony because of the illegal fireworks.
They described the house as containing a large cache of commercial-grade fireworks and said there had been complaints about the property previously.
Arlene Fiero, who lives next to the house, said there have been issues with the home before so as soon as she heard something she started recording. Her footage shows her asking about the safety of other people in her own home and then a series of explosions rips out the glass, creating a terrifying scene.
"I immediately just thought of my parents, they were in the front house," she said. "My small animals are in the area, I called for them. I wasn't able to do much but get myself out to safety."
Outside the home, she saw a car in flames and thinks perhaps that was the source of one of the explosions that shook her home.
Neighbors across the street had their home's windows shattered. Their grandchildren were playing in the back yard at the time and narrowly avoided serious injury.
Suzie Owens says she was physically thrown more than once by the force of the multiple explosions.
"We all started screaming. I came outside, then I hear gunshots, it sounded like," Owens said. "Then it was fireworks. It was another boom, an explosion. It literally threw me off the grass."
She went inside the house and another explosion threw her against the wall.
"No one got hurt," she said. "I'm glad the little one decided to move quickly or that glass would've fallen on her. She was in the bedroom."
Several blocks from the scene, footage recorded by a witness showed smoke rising above the fire while the distinctive sound of fireworks exploding was clearly audible. Meanwhile, multiple car alarms that were set off could also be heard.
A later tweet from the city said the fire erupted after "a large amount of fireworks at a house ignited." At least one other home was also burning, along with several outdoor structures on a ranch-like property.
Firefighters managed to free a horse on the property that was trapped against a fence near a pile of burning debris.
About 50 firefighters were involved in battling the flames. Officials were concerned about the possibility of more unexploded fireworks at the home. A bomb squad was expected to comb the scene before firefighters moved in to the home.