LOS ANGELES (AP) — A cache of illegal fireworks seized at a South Los Angeles home exploded Wednesday evening, damaging nearby homes and cars and injuring at least 16 people, three of them seriously, authorities said.

Police had called in a bomb squad after a tip led them to seize some 5,000 pounds (2,268 kilograms) of illegal home-made and China-manufactured pyrotechnics at about noon, police said.

One man was arrested on suspicion of possessing fireworks and destructive devices and also on suspicion of child endangerment because two children were found at the home, police said.

Some of the fireworks appeared to be large mortar-sized devices used for commercial purposes.

“I would expect multiple houses destroyed had those explosives gone up,” LAPD Capt. Robert Long told KABC-TV.

Pallet-loads of fireworks were placed into an LAPD tractor-trailer and hauled away for disposal but at some point, some of the devices that had been placed inside an armored container on an LAPD big-rig exploded in a burst of flame, demolishing the truck. The blast, caught by news crews, also knocked a nearby car on its side, smashed the windows of several others and blew out windows in a neighboring home.

“Some of the fireworks were being stored in our Bomb Squad trailer as a precautionary measure" when there was an explosion, an LAPD tweet said, adding that it was unknown what sparked the blast.

However, a KCBS-TV reporter said that before the explosion at around 7:30 p.m., journalists were warned that some fireworks were going to be destroyed inside the truck and the warning “Fire in the hole!" was shouted several times.

One news helicopter pilot said the blast shook his aircraft, and some residents two blocks away say they were jolted by the explosion.

Six people were taken to a hospital, three with serious and three with minor injuries, a Fire Department tweet said.

In addition, 9 LAPD officers and a federal Bureau of Alcohol, Tobacco, Firearms and Explosives officer had minor injuries and were taken to the hospital in fair condition, fire officials said.

Police evacuated nearby homes. Building inspectors were evaluating some homes to determine if they were safe.

In March, a massive fireworks explosion left two people dead in Southern California and caused at least $3.2 million in damage.