By CBSLA Staff

LOS ANGELES (CBSLA) – Los Angeles Police Chief Michel Moore issued an apology Monday for a fireworks explosion in a South L.A. neighborhood last month which injured 17 people and damaged several homes. He also revealed that bomb squad technicians likely miscalculated the weight of the explosives that were placed in the truck.

FILE — Investigation in a fireworks explosion that destroyed a LAPD bomb squad vehicle in the 700 block of East 27th Street. July 4, 2021. (Irfan Khan/Los Angeles Times/Getty Images)

Moore gave the apology Monday morning outside LAPD headquarters at a news conference held with agents from the Bureau of Alcohol, Tobacco, Firearms and Explosives.

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“I want to personally express my apologies to every resident, business operator and customer that was traumatically impacted by this incident,” Moore said.

The botched explosion occurred on the night of June 30 at East 27th and San Pedro streets.

The LAPD had discovered about 32,000 pounds of illegal fireworks at a nearby home and arrested a 27-year-old man who lived there. Moore said the illegal fireworks included about 200 M-80 style explosives.

Several pounds of the illegal fireworks – which were deemed too dangerous to travel with — were placed in a specialized armored truck designed for controlled detonations.

However, what was supposed to be a controlled detonation instead turned into a massive explosion. Ten LAPD officers, one ATF officer and six civilians were hurt.

Moore said 13 businesses, 22 residential properties and 37 vehicles were either damaged or destroyed.

He disclosed that the ATF National Response Team (NRT), which is investigating the cause of the explosion, has determined that there are two possible hypotheses for what caused the blast. There may have been a defect in the truck, which is known as a total containment vessel (TCV). Or, the fireworks that were placed in the truck exceeded the vehicle’s capacity.

“First, there was a defect of the TCV,” Moore said. “Second, the net explosive weight…placed into the TCV exceeded the rated amount for that vessel. Or some combination of these two hypotheses.”

Moore revealed that, prior to the detonation, the bomb squad estimated that the total net weight of explosives placed in the truck was 16.5 pounds.

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However, the ATF NRT’s analysis in the days afterwards determined that there were was likely just over 42 pounds of explosives in the truck.

“When all the illegal explosives and countercharges were placed in the TCV, the NRT calculated the total weight was just over 42 pounds of net explosive weight,” Moore said. “The LAPD Bomb Squad estimation totaled 16.5 pounds…We have miscalculations that are significant.”

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Many of the displaced residents have still been unable to return to their homes. One victim told CBSLA that she and her family are now sleeping in a shoe store they own down the street because they have nowhere else to go.

Several families have filed claims against the city.

Prosecutors said the suspect, Arturo Ceja III purchased most of the explosives from a dealer in Pahrump, Nevada. In addition to the commercial fireworks, the initial search of Ceja’s residence led to the discovery of more than 140 other homemade fireworks — typically referred to M devices of varying sizes — as well as explosives-making components, including hobby fuses that matched the fuse on a homemade mortar shell wrapped in tin foil discovered inside the residence, according to a court affidavit.

Ceja faces federal charges of illegally transporting explosives without a license. He is scheduled to be arraigned Aug. 2.

Meanwhile, at 3 p.m. Monday, the 27th Street Incident Community Resource Center will officially launch at the YMCA at 1006 E. 28th St., according to the office of City Councilman Curren Price.

The new resource center will serve as the designated location where victims can connect with a wide range of services, including opportunities to file a claim, obtain mental health and wellness referrals, as well as other supportive services. The site will include representatives from Price’s office, the city attorney and city clerk, mental health and wellness staff, as well as members of the non-profit All Peoples Community Center who will offer food and clothing.

The supervisors who were on the scene the day of the explosion have been pulled from the field. The federal report is expected to be finalized within 30 days.

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(© Copyright 2021 CBS Broadcasting Inc. All Rights Reserved. City News Service contributed to this report.)