Several police and fire units responded to the scene – about 35 miles east of downtown Los Angeles – at around 12:30 pm PST. A house was on fire, the department said.
Dramatic video from the cell phone shows fireworks and a cloud of smoke rising above the scene.
“An explosion of this size, I imagine there could be some damage to the houses directly next to it,” said city spokesman Dan Bell.
Reina Jimenez, who lives near the blast area, told CNN that there were at least three explosions.
“The first explosion was like an earthquake or something that fell near us,” said Jimenez. “The second explosion was bigger and louder. It shook the whole house … My husband started shooting when the third explosion happened. It was also very big and noisy and it rocked the house again. We were worried that the explosion would hit the house then we started to prepare the children to leave. ”
The deaths occurred “in the area” of the explosion and the two individuals were not publicly identified, Bell said. There were people in the house who managed to get out safely, according to a fire department spokesman.
An additional minor injury has been reported, the fireman said. The explosion is under investigation.
Evacuations were ordered on at least three streets in the neighborhood and firefighters warned residents to stay away from the area.
Several structures were damaged and covered with rubble, the fireman said. At least one horse was released from the immediate area by firefighters.
Fireworks are banned in the city and cannot be sold, bought, stored, used or transported in the city, officials told CNN.
Jimenez told CNN that his family has heard fireworks exploding in the general area for the past five years.
“About once a week, one or more fires during the summer or around the 4th of July, and we just got used to them,” she said.
However, people have complained on the Ring neighborhood app about the problem before, she said.
Alexandra Meeks and Jessica Myers of CNN reported from Los Angeles and Amir Vera wrote and reported from Atlanta. CNN’s Janine Mack contributed to this report.